Category: Class 10

AP State Board Syllabus AP SSC 10th Class Physics Solutions Chapter 6 Refraction of Light at Curved Surfaces Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Physics Solutions 6th Lesson Refraction of Light at Curved Surfaces

10th Class Physics 6th Lesson Refraction of Light at Curved Surfaces Textbook Questions and Answers

Review of Your Previous Knowledge

Question 1.
Have you ever touched a magnifying glass with your hand?
Answer:
Yes.

Question 2.
Have you touched the glass in the spectacles used for reading with your hand?
A. Yes.

Question 3.
Is it a plane or curved surface?
Answer:
Curved surface.

Question 4.
Is it thicker in the middle or at the edge?
Answeer:
Magnifying glass and some spectacle are thicker in middle whereas some spectacles are thicker at edge.

Improve Your Learning

Question 1.
A man wants to get a picture of a zebra. He photographed a white donkey after fitting a glass, with black stripes, on to the lens of his camera. What photo will he get? Explain. (AS1)
(OR)
A person wants to get a picture of zebra and he photographed a white donkey fitting a glass with black stripes. Does he get photo of zebra? Explain.
Answer:
The person was unable to gel the picture <>l zebra because only two rays are enough to form complete image after convergence. So he will get the image of white donkey but the intensity may be less.
(OR)
He will get a picture of while donkey because e\ery part of lens forms an image so if you cover lens with stripes still it forms a complete image. However, the intensity of the image will be reduced.

Question 2.
Two converging lenses are to be placed in the path of parallel rays so that the rays remain parallel after passing through both lenses. How should the lenses be arranged? Explain with a neat ray diagram. (AS1)
Answer:

• Two lenses are placed in the path of parallel rays as shown in figure.
• The first lens is placed in the direction of parallel lines, which converges at focus.
• The second lens is arranged so that it is the focus of 2nd then emerging rays will be parallel.

Question 3.
The focal length of a converging lens is 20 cm. An object is 60 cm from the lens. Where will the image be formed and what kind of image is it? (AS1)
Answer:
f = 20 cm (by sign conversion f = + 20 cm)
u = 60 cm (by sign conversion u = – 60 cm)

Image will be formed at 30cm in between F₁, and 2F1. Image is real, inverted and diminished.

Question 4.
A double convex lens has two surfaces of equal radii ‘R’ and refractive index n = 1.5. Find the focal length ‘f’. (AS1)
(OR)
What is the focal length ‘f, when its double convex lens has two surfaces of equal radii ‘R’ and refractive index n = 1.5?
Answer:
R₁ = R₂ = R (suppose)
Focal length (f) = ?; Refractive index (n) = 1.5

∴ Focal length of lens = Radius of curvature of surface.

Question 5.
Write the lens maker’s formula and explain the terms in it. (AS1)
(OR)
Ravi wants to make a lens. Which formula he has to follow ? Write the formula and explain the terms in it.
(OR)
Write lens formula.
Answer:
Lens maker’s formula:
\(\frac{1}{\mathrm{f}}=(\mathrm{n}-1)\left(\frac{1}{\mathrm{R}_{1}}-\frac{1}{\mathrm{R}_{2}}\right)\)
n = Refractive index of the medium
R₁ = Radius of curvature of 1 st surface
R₂ = Radius of curvature of 2nd surface
f = Focal length

Question 6.
How do you verify experimentally that the focal length of a convex lens is increased when it is kept in water? (AS1)
(OR)
Write an activity to show that the focal length of a lens depends on its surrounding medium.
Answer:
Aim :
To prove focal length of convex lens is increased when it is kept in water.

Apparatus :
Convex lens, water, cylindrical vessel, circular lens holder, stone.

Procedure :

1. Take a cylindrical vessel like glass tumbler.
2. Its height must be greater than the focal length of lens, (the around four times focal length of lens).
3. Keep a black stone inside the vessel at its bottom.
4. Pour the water into the vessel such that the height of the water level from the top of the stone is greater than the focal length of lens.
5. Now dip the lens horizontally using a circular lens holder.
6. Set the distance between stone and lens that is equal to or less than focal length of lens.
7. Now see the stone through the lens.
8. We can see the image of the stone.
9. If we dip the lens to a certain height which is greater than the focal length of lens in air, still we can see the image.
10. This shows that the focal length of convex lens has increased in water.
11. Thus we conclude that the focal length of lens depends upon the surrounding medium.

Note : For convenience, use 5 or 10 cm focal length convex lens.

Question 7.
How do you find the focal length of a lens experimentally? (AS1)
Answer:

• Take the lens (Ex : Convex), which focused towards the distant object.
• A white coated screen (Ex : White paper) is placed on the other side of the lens.
• Adjust the screen till you get a clear image of the object.
• At this position measure the distance between the lens and screen which is equal to the focal length of the lens.

Question 8.
Harsha tells Siddhu that the double convex lens always behaves like a convergent lens. But Siddhu knows that Harsha’s assertion is wrong and corrected Harsha by asking some questions. What are the questions asked by Siddhu? (As2)
Answer:
The questions asked by Siddhu :

1. Is the object placed beyond 2f point?
2. Is the object located at 2f point?
3. Is the object located in between the 2f and the focal point?
4. Is the object located at the focal point?
5. Is the object located in front of the focal point?
6. Is the lens kept in a medium with refractive index less than lens or more than lens?

Question 9.
Assertion (A): A person standing on the land appears taller than his actual height to a fish inside a pond. (AS2)
Reason (R) : Light bends away from the normal as it enters air from water.
Which of the following is correct? Explain.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true and R is not the correct explanation of A.
c) A is true but R is false.
d) Both A and R are false.
e) A is false but R is true.
Answer:
Answer a is correct.
Explanation :
Because the light travelling from water to air it bends away from the normal so the fish observes the apparent image of the person, appears taller than his original.

Question 10.
A convex lens is made up of three different materials as shown in the figure Q-10. How many of images does it form? (AS2)

Answer:

• A lens made of three different materials of refractive indices say n₁, n₂ and n₃.
• These three materials will have three different refractive indices. Thus for a given object it forms three images.

Question 11.
Can a virtual image be photographed by a camera? (AS2)
Answer:
Yes, we can.
Ex : – A plane mirror forms a virtual image, we can able to take photograph of that image in plane mirror.

Question 12.
You have a lens. Suggest an experiment to find out the focal length of the lens. (AS3)
(OR)
Through an experiment, find out the focal length of the lens.
Answer:
Aim :
To find focal length of given lens.

Apparatus :
Object (candle), convex lens, v – stand, screen.

Procedure :

• Take a v-stand and place it on a long table at the middle.
  Place a convex lens on the v-stand. Imagine the principal axis of the lens.
• Light a candle and ask your friend to take the candle far away from the lens along the principal axis.
• Adjust a screen (a sheet of white paper placed perpendicular to the axis) which is on other side of the lens until you get an image on it.
• Measure the distance of the image from the v-stand of lens (image distance V) and also measure the distance between the candle and stand of lens (object distance ‘u’). Record the values in the table.

• Now place the candle at a distance of 60 cm from the lens, try to get an image of the candle flame on the other side on a screen. Adjust the screen till you get a clear image.
• Measure the image distance V and object distance ‘u’ and record the values in table.
• Repeat the experiment lor various object distances like 50 cm, 40 cm, 30 cm, etc. Measure the image distances in all cases and note them in table.
• Using the formula \(\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\), find f in all the cases. We will observe the value ‘f is equal in all cases. This value off is the focal length of the given lens.

Question 13.
Let us assume a system that consists of two lenses with focal length f₁, and f₂ respectively. How do you find the focal length of the system experimentally, when
i) two lenses are touching each other
ii) they are separated by a distance ‘d’ with common principal axis? (AS3)
Answer:
Experimental Proof:
i) Two lenses are touching each other :
Aim :
To find focal length of combination of two convex lenses, touching each other. Material required : Convex lenses – 2 (with known focal lengths say f, and f2); V-stands – 2, candle, screen scale.

Procedure:

• Place two V-stands with two convex lenses as they touch each other on a table.
• Place a candle (object) far away from the lenses.
• Adjust a screen, which is placed other side of the lenses until we get a clear image on it.
• At that position, measure the image distance (v) and object distance (u).
• Do this experiment for several object distances and record in the given table.

ii) They are separated by a distance of ‘d’ :
Procedure :

• Now place v-stands along with lenses with distance’d’.
• Do the same procedure again.
• Record the observations in the given table.
• Find the average of the ‘f’_comb.

Question 14.
Collect the information about the lenses available in an optical shop. Find out how the focal length of a lens may be determined by the given power’ of the lens. (AS4)
Answer:
I had collected the information regarding different lenses available at optical shops.
The relationship between power and focal length is power (D) = \(\frac{1}{f}\). f is in meters.

Power of lens in diopters	Type of lens	Focal length
0.25	Convex	400 cm
0.5	Convex	200 cm
1	Convex	100 cm
-2	Concave	50 cm
– 1	Concave	– 100 cm
-0.5	Concave	– 200 cm
-0.25	Concave	– 400 cm

Question 15.
Collect the information about lenses used by Galileo in his telescope. (AS4)
(OR)
What lenses are used by Galileo in his telescope?
Answer:

A Galilean telescope is defined as having one convex lens and one concave lens. The concave lens serves as the ocular lens or the eye piece, while the convex lens serves as the objective. The lens are situated on either side of a tube such that the focal point of the ocular lens is the same as the focal point for the objective lens.

Question 16.
Use the data obtained by activity – 2 in table-1 of this lesson and draw the graphs of u vs v and \(\frac{1}{u}\) vs \(\frac{1}{v}\) (AS5)
(OR)
By obtaining data from activity – 2 in table – 1 of this lesson, draw the graphs of u vs v and \(\frac{1}{u}\) vs \(\frac{1}{v}\)
Answer:
Graph of u – v using data obtained by activity – 2. Take lens with focal length 30 cm.

Object distance (u)	Image distance (v)	Focal length (f)
60 cm	60 cm	30 cm
50 cm	75 cm	30 cm
40 cm	120 cm	30 cm

The graph looks like this

The shape of the graph is rectangular hyperbola.

Graph of \(\frac{1}{u}\) – \(\frac{1}{v}\)

For these values the graph is straight line which touches the axis as shown in figure.

Question 17.
Figure shows ray AB that has passed through a divergent lens. Construct the path of the ray up to the lens if the F position of its foci is known. (AS5)

Answer:

The path of the ray up to the lens if the position of foci is known for ray AB is diverging lens or concave lens path.

Question 18.
Figure shows a point light source and its image produced by a lens with an optical axis N₁, N₂. Find the position of the lens and its foci using a ray diagram. (AS5)

Answer:

1. The object is in between focus and optic centre.
2. The image is virtual, erect and magnified. Nv
3. l is the lens, ‘O’ is the object and T is the image.

Question 19.
Find the focus by drawing a ray diagram using the position of source S and the image S’ given in the figure. (AS5)

Answer:

1.  Image is real.
2. l’ is lens, ‘O’ is object and T is image.
3.  Lens is convex.

(Or)

1. Image is real.
2. l’ is lens, ‘O’ is object and ‘I’ is image.
3. Lens is convex.

Question 20.
A parallel beam of rays is incident on a convergent lens with a focal length of 40 cm. Where should a divergent lens with a focal length of 15 cm be placed for the beam of rays to remain parallel after passing through the two lenses? Draw a ray diagram. (AS5)
Answer:

1. A parallel beam of rays when incident on a convergent lens, after refraction they meet at the focus of the lens.

2. A beam of rays which is incident on a divergent lens, after refraction, pass parallel to the principal axis. If we extend these incident rays, they seems to meet at focus of the lens.

3. Hence the divergent lens should be kept at 25 cm distance from convergent lens (40 – 15 = 25 cm) as shown in the figure.

PF = 40 cm (Focal length of convergent lens)
P’F = 15 cm (Focal length of divergent lens)
PP’ = 40 – 15 = 25 cm (Position of divergent lens)

Question 21.
Draw ray diagrams for the following positions and explain the nature and position of image.
i) Object is placed at 2F₂
ii) Object is placed between F₂ and optic centre P. (AS5)
Answer:
i) Object is placed at 2F₂:

Nature : Real, inverted and diminished.
Position : Image is formed on the principal axis between the points F₁, and 2F₁.

ii) Object is placed between F₂ and optic centre P :

Nature : Virtual, erect and magnified.
Position : Same side of the lens where object is placed.

Question 22.
How do you appreciate the coincidence of the experimental facts with the results obtained by a ray diagram in terms of behaviour of images formed by lenses? (AS6)
Answer:

• Ray diagrams are very useful in optics.
• By the ray diagrams, we can easily find the values of image distance, object distance, focal length, radius of curvature, magnification, etc.
• These results are exactly equal to the result gotten by an experiment.
• For example : In the experiment, with a convex lens, we get clear image of an object, on a screen by adjusting the screen.

Then, we measure the image distane (v) practically. This takes more time and requires equipped lab also.

But, by simply draw a ray diagram on a paper, we can get exact image distance (v) very easily, without lab.

• So, ray diagrams are very useful in the construction of microscopes, telescopes, etc.
• Hence, one can trust and depend on the result of ray diagrams instead of several lab experiments.
• So, I appreciate the ray diagrams.

Question 23.
Find the refractive index of the glass which is a symmetrical convergent lens if its focal length is equal to the radius of curvature of its surface. (AS7)
Answer:
Given that lens is convergent symmetrical

Question 24.
Find the radii of curvature of a convexo – concave convergent lens made of glass with refractive index n = 1.5 having focal length of 24 cm. One of the radii of curvature is double the other. (AS7)
Answer:

Question 25.
The distance between two point sources of light is 24 cm. Where should a convergent lens with a focal length of f = 9 cm be placed between them to obtain the images of both sources at the same point? (AS7)
Answer:
For Source S₁ :

∴ The convex lens may be placed between the two sources, such that a distance of 18 cm from one source, and 6 cm from other source.

Question 26.
Suppose you are inside the water in a swimming pool near an edge. A friend is standing on the edge. Do you find your friend taller or shorter than his usual height? Why? (AS7)
(OR)
If your friend is standing near an edge of the swimming pool and you are in the water, do you find he is taller or shorter than his usual height?
Answer:

1. My friend appears to be taller because the light is travelling from rarer to denser.
2. The rays bend in such away that they seems to be coming from long distance.
3. So it is actually apparent image of my friend which appears to be taller due to refraction.

Fill in the Blanks

1. The rays from the distant object, falling on the convex lens pass through ……………….. .
2. The ray passing through the ……………….. of the lens is not deviated.
3. Lens formula is given by ……………….. .
4. The focal length of the plano-convex lens is 2R where R is the radius of curvature of the surface. Then the refractive index of the material of the lens is ……………….. .
5. The lens which can form real and virtual images is ……………….. .
Answer:

1. Tocus
2. optical centre
3. \(\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\)
4. 1.5
5. convex lens

Multiple Choice Questions

1. Which one of the following materials cannot be used to make a lens?
A) water
B) glass
C) plastic
D) clay
Answer:
D) clay

2. Which of the following is true?
A) The distance of virtual image is always greater than the object distance for convex lens.
B) The distance of virtual image is not greater than the object distance for convex lens.
C) Convex lens always forms a real image.
D) Convex lens always forms a virtual image.
Answer:
B) The distance of virtual image is not greater than the object distance for convex lens.

3. Focal length of the plano-convex lens is when its radius of curvature of the surface is R and n is the refractive index of the lens.

4. The value of the focal length of the lens is equal to the value of the image distance when the rays are
A) passing through the optic centre
B) parallel to the principal axis
C) passing through the focus
D) in all the cases
Answer:
D) in all the cases

5. Which of the following is the lens maker’s formula?

Answer:
C

10th Class Physics 6th Lesson Refraction of Light at Curved Surfaces Additional Questions and Answers

Question 1.
Derive a relation between refractive indices of two media (n₁, n₂), object distance (u), image distance (v) and radius of curvature (R) for a curved surface.
(OR)
Derive \(\frac{\mathbf{n}_{2}}{\mathbf{v}}-\frac{\mathbf{n}_{1}}{\mathbf{u}}=\frac{\mathbf{n}_{2}-\mathbf{n}_{1}}{\mathbf{R}}\)
(OR)
Derive curved surface formula.
Answer:

• Consider a curved surface separating two media of refractive indices n₁, and n₂.
• A point object is placed on the principal axis at point ‘O’.
• The ray which travels along the principal axis passes through the pole undeviated.
• The second ray, which forms an angle with a princi¬pal axis, meets the interface at A. The angle of incidence is Q₁. The ray bends and passes through the second medium along the line AI. The angle of refraction is Q₂.
• The two refracted rays meet at I and the image is formed there.
• 6) Let the angle made by the second refracted ray with principal axis be γ and the angle between the normal and principal axis be β.
• From figure,

PO = u (object distance), PI = v (Image distance),
PC = R (radius of curvature) and n₁, n₂ are refractive indices of the media.
From ∆ACO, θ₁ = α + β
∆ACI, β = θ₂ + γ
⇒ θ₂ = β – γ
According to Snell’s law, n₁sin θ₁ = n₂ sin θ₂.
∴ n₁ sin (α + β) = n₂ sin (β – γ) …………….. (1)
As per paraxial approximation,
sin (α + β) = α + β and sin (β – γ) = β – γ.
∴ (1) ⇒ n₁(α + β) = n₂ (β – γ)
⇒ n₁ α + n₁β = n₂ β – n₂ γ — (2)
Since all angles are small, we can write

∴ This is the required relation for curved surfaces.

Question 2.
Derive expression for lens maker’s formula.
(OR)
Prove \(\frac{1}{\mathbf{f}}=(\mathbf{n}-\mathbf{1})\left(\frac{1}{\mathbf{R}_{1}}-\frac{1}{\mathbf{R}_{2}}\right)\).
Answer:

Procedure :

• Imagine a point object ‘O’ placed on the principal axis of the thin lens
• Let this lens be placed in a medium of refractive index n_a and let refractive index of lens be n_b.
• Consider a ray, from ‘O’ which is incident on the convex surface of the lens with radius of curvature R₁ at A.
• The incident ray refracts at A.
• It forms image at Q, if there were no concave surface.
• From figure Object distance PO = – u;

Image distance PQ = v = x
Radius of curvature R = R₁
n₁ = n_a and n₂ = n_b.

• But the ray that has refracted at A suffers another refraction at B on the concave surface with radius of curvature (R₂).
• At B the ray is refracted and reaches I.
• The image Q of the object due to the convex surface. So I is the image of Q for concave surface.
• Object distance u = PQ = + x
  Image distance PI = v
  Radius of curvature R = – R₂
• The refraction of the concave surface of lens is medium -1 and surrounding is medium – 2.
  ∴ n₁ = n_b and n₂ = n_a

Question 3.
Derive the lens formula.
Answer:
1. Consider an object 00′ placed on the principal axis in front of a convex lens as shown in the figure. Let II’ be the real image formed by the lens, i.e. the other side of it.

2. From the figure : PO, PI, PFt are the object distance, image distance and focal length respectively.

10th Class Physics 6th Lesson Refraction of Light at Curved Surfaces InText Questions and Answers

10th Class Physics Textbook Page No. 64

Question 1.
What happens to a ray that is incident on a curved interface separating the two media? Are the laws of refraction still valid?
Answer:
It undergoes deviation from its path. Yes, the laws of reflection are still valid.

Question 2.
How do rays betid when they are incident on a curved surface?
Answer:
A ray will bend towards the normal when it travels from rarer to denser medium and bends away from the normal when it travels from denser to a rarer medium.

10th Class Physics Textbook Page No. 65

Question 3.
What happens to ray that travels along the principal axis? Similarly, a ray that travels through the centre of curvature?

Answer:
According to Snell’s law the ray which travels along the normal drawn to the surface does not deviate from its path. Hence both rays in the given condition travel along normal, so they do not deviate.

Question 4.
What difference do you notice in the refracted rays in 4 (a) and 4 (b)? What could be the reason for that difference?

Answer:

• In figure 4 (a) ray travelling parallel to the principal axis strikes a convex surface and passes from a rarer medium to a denser medium.
• In figure 4 (b) a ray travelling parallel to the principal axis strikes a convex surface passes from a denser medium to a rarer medium.
• Figure 4 (a) : The refracted ray moves towards the normal.
• Figure 4 (b) : The refracted ray moves away from the normal.
  Reason : The main reason is that light passes through different media.

10th Class Physics Textbook Page No. 66

Question 5.
What difference do you notice in refracted rays in 4 (c) and 4 (d)? What could be the reasons for that difference?
(OR)
Draw the ray diagrams when the incident ray passes through the curved surfaces.
a) Rarer medium to denser medium.
b) Denser medium to rarer medium.

Answer:

• In figure 4 (c) a ray travelling parallel to the principal axis strikes a concave surface and passes from a denser medium to a rarer medium.
• In figure 4 (d) a ray travelling parallel to the principal axis strikes a concave surface and passes from a rarer medium to a denser medium.

Reasons :

• Figure 4 (c) :The refracted ray reaches a particular point on the principal axis.
• Figure 4 (d) : The refracted ray moves away from the principal axis.
• The main reason is that light passes through different media.

Question 6.
You might have observed that a lemon in the water of a glass tumbler appears bigger than its actual size, when viewed from the sides of tumbler.
1) How can you explain this (appeared) change in size of lemon?
Answer:
It can be explained by using refraction. When light travels from one medium to another medium it undergoes refraction.

2) Is the lemon that appears bigger in size an image of lemon or is it the real lemon?
Answer:
That is image of lemon.

3) Can you draw a ray diagram to explain this phenomenon?
Answer:

10th Class Physics Textbook Page No. 70

Question 7.
What happens to the light ray when a transparent material with two curved surfaces is placed in its path?
Answer:
The light ray undergoes refraction.

Question 8.
Have you heard about lenses?
Answer:
Yes, we have heard about lenses. A transparent material bounded by two spherical v surfaces is called lens.

Question 9.
How does a light ray behave when it is passed through a lens?
Answer:
A light ray will deviate from its path in some cases and does not deviate in some other cases.

10th Class Physics Textbook Page No. 72

Question 10.
How does the lens form an image?
Answer:
Lens forms an image through converging light rays or diverging light rays.

Question 11.
If we allow a light ray to pass through the focus, which path does it take?
Answer:
The ray passing through the focus takes a parallel path to principal axis after refraction.

10th Class Physics Textbook Page No. 73

Question 12.
What happens when parallel rays of light fall on a lens making some angle with the principal axis?
Answer:’
The rays converge at a point (or) appear to diverge from a point lying on the focal plane.

Question 13.
What do you mean by an object at infinity? What type of rays fall on the lens?
Answer:
The distance between the lens and the object is very much greater than when compared to object size is known as object at infinity. Parallel rays fall on the lens.
The object at infinity means distant object. The rays falling on the lens from an object at infinity are parallel to principal axis.

10th Class Physics Textbook Page No. 77

Question 14.
Could you get an image on the screen for every object distance with a convex lens?
Answer:
No, when the object is placed between pole and focus we will get virtual, erect and enlarged image on the other side of the- object.

Question 15.
Why don’t you get an image for certain object distances?
Answer:
Because at those distances the light rays diverge each other.

Question 16.
Can you find the minimum limiting object distance for obtaining a real image? What do you call this minimum limiting object distance?
Answer:
Yes, this minimum limiting object distance is called focal length.

Question 17.
When you do not get an image on the screen, try to see the image with your eye directly from the place of the screen. Could you see the image? What type of image do you see?
Answer:
Yes, we can see the image. This is a virtual image which we cannot capture on screen.

Question 18.
Can you find the image distance of a virtual image? How could you do it?
Answer:
We can find the image distance of virtual image by using lens formula \(\frac{1}{\mathrm{f}}=\frac{1}{\mathrm{v}}-\frac{1}{\mathrm{u}}\) (if we know the focal length of lens and object distance.)

10th Class Physics 6th Lesson Refraction of Light at Curved Surfaces Activities

Activity – 1

Question 1.
Write an activity to observe the light refraction at curved surface.
Answer:
Procedure and observation :

• Draw an arrow of length 4 cm usfng a black sketch pen on a thick sheet of paper.
• Take an empty cylindrical-shaped transparent vessel.
• Keep it on the table.
• Ask your friend to bring the sheet of paper on which arrow was drawn behind the vessel while you look at it from the other side.
• We will see a diminished image of the arrow.
• Ask your friend to fill vessel with water.
• Look at the arrow from the same position as before.
• We can observe an inverted image.

Explanation :

• In the first case, when the vessel is empty, light from the arrow refracts at the curved interface, moves through the glass, enters in to air then it again undergoes refraction on the opposite curved surface of vessel and comes out into the air.
• In this way light travels through two media, comes out of the vessel and forms a diminished image.
• In the second case, light enters the curved surface, moves through water, comes out of the glass and forms an inverted image.

Lab Activity

Question 2.
Write an activity to know the characteristics of image due to convex lens at various distances.
Answer:
Aim:
Determination of focal length of bi-convex lens using UV method.

Material Required :
V Stand, convex lens, light source, screen, meter scale. Take a V-stand and place it on a long (nearly 2m) table at the middle. Place a convex lens on the v-stand. Imagine the principal axis of the lens. Light a candle and ask your friend to take the candle far away from the lens along the principal axis. Adjust a screen (a sheet of white paper placed perpendicular to the axis) which is on other side of the lens until you get an image on it.

Procedure :

1. Take a V-stand and place a convex lens on this stand.
2. Imagine the principal axis of the lens.
3. Light a candle and ask your friend to take the candle far away from the lens along the principal axis.
4. We use a screen because it forms a real image generally which will form on a screen. Real images cannot be seen with an eye.
5. Adjust the screen, on other side of lens until clear image forms on it.
6. Measure the distance of the image from the stand and also measure the distance between the candle and stand of lens.
7. Now place the candle at a distance of 60 cm from the lens such as the flame of the candle lies on the principal axis of the lens.
8. Try to get an image of candle flame on the other side on a screen.
9. Adjust the screen till you get a clear image.
10. Measure the distance of image (v) from lens and record the value of’u’ and V in the table.
11. Repeat this for various distances of images; in all cases note them in the table.

Observation :

Conclusion : From this we conclude that a convex lens forms both real and virtual images when object is placed at various positions.

AP State Board Syllabus AP SSC 10th Class Biology Important Questions Chapter 3 Transportation.

AP State Syllabus SSC 10th Class Biology Important Questions 3rd Lesson Transportation

10th Class Biology 3rd Lesson Transportation 1 Mark Important Questions and Answers

Question 1.
What happens if blood platelets are absent in blood?
Answer:

1. Blood clotting do not be takes place.
2. So bleeding from the injuries occurs continuously leads to death of the person.

Question 2.
When do you think that our pulse rate goes up?
Answer:
Running, Exercise, Fear, Tension, Climbing up stairs.

Question 3.
List out the apparatus required to conduct root pressure experiments in plant.
Answer:
Clamp, glass tube, strong rubber tube, potted plant.

Question 4.
What happens if there are no valves in the Heart?
Answer:

1. The valves between each atrium and its ventricles are one way valves. They allow the blood to flow from atrium to the ventricles without any hindrance, back flow of blood is stopped.
2. If there are no valves in the heart, blood flow will not be proper, heart can not pump the blood properly into the blood vessels.

Question 5.
What is meant by pulse?
Answer:

1. When we keep our finger at the wrist where the artery is passing into the hand, we feel the pressure of blood moving in it. This is the pulse,
2. The rate of pulse will be equal to the number of heart beats.

Question 6.
Two person’s Blood Pressure is like this:

Whose Blood Pressure is high? What does it indicate?
Answer:
The normal blood pressure is 120/80
The numerator 120 indicates systolic pressure.
The denominator 80 indicates diastolic pressure.
Ramaiah B.P. is 140/80. So he has high blood pressure.

Question 7.
How does lymph differ from blood?
Answer:

1. RBC are present in blood, RBC are absent in lymph.
2. Blood is Red in colour, lymph is colourless.

Question 8.
Name the largest artery in the body.
Answer:
Aorta is the largest artery in the body.

Question 9.
Name the apparatus, shown in the figure below.

Answer:
Sphygmomanometer.

Question 10.
List out the materials you have used to observe the goat heart in your laboratory.
Answer:

1. Freshly collected specimen of goat’s heart
2. Soda straws
3. Used pen refils
4. The sharp and long blade
5. Tray
6. A jug of water
7. Dissection scissors
8. Forceps
9. Gloves

Question 11.
Name any two valves present in human heart.
Answer:

1. The valve that is present between left atrium and left ventricle is mitral valve or bicuspid valve.
2. The valve that is present between right atrium and right ventricle is the tricuspid valve.

Question 12.
Siri injured while playing, and the blood is flowing continuously from the wound, what may be the reason for this?
Answer:
a) Vitamin – K is helpful for clotting of blood. Perhaps Siri might be suffering from a deficiency of Vitamin – K. So, blood is flowing continuously from the wound,
b) He may be suffering from thalassemia.

Question 13.
Prepare two questions, which you ask the doctor to know more details about high blood pressure.
Answer:
a) How can we know that we have high blood pressure?
b) What are the adverse affects of high blood pressure?
c) How can we prevent high blood pressure?
d) What diet should you prescribe for high BP patients?

Question 14.
What is the number of heart beats in new born babies.
Answer:
Number of heart beats in new born babies are 100-150 times.

Question 15.
What is the number of heart beats in well trained adult athletes.
Answer:
Number of heart beats in well trained adult athletes are 40 – 60 times.

Question 16.
Where is heart located in our body? How is it protected?
Answer:
Heart is located in between the lungs and protected by rib cage.

Question 17.
What is the size of our heart?
Answer:
The size of our heart is approximately size of our fist.

Question 18.
What is the shape and structure of heart?
Answer:
The heart is a pear shaped structure, triangle in the outline, wider at the anterior end and narrower at the posterior end.

Question 19.
What protects the heart from shocks?
Answer:
The space between the two layers of pericardial membrane (Pericardium) is filled with pericardial fluid which protects the heart from shocks.

Question 20.
What divides the heart into four parts?
Answer:
The heart is divided into four parts by grooves.

Question 21.
What are the blood vessels that supply blood to muscles of the heart?
Answer:
The blood vessels that supply blood to muscles of the heart are coronary vessels.

Question 22.
Which is the largest artery in the body?
Answer:
Aorta is the largest artery in the body.

Question 23.
Which artery supplies deoxygenated blood from heart to lungs?
Answer:
Pulmonary artery supplies deoxygenated blood from heart to lungs.

Question 24.
What are the two veins that collect blood from anterior parts and posterior parts of the body?
Answer:
Superior venacava (pre-caval vein) collects blood from anterior parts of the body and inferior venacava (Post-caval vein) collects blood from posterior parts of the body.

Question 25.
Who studied the veins in the leg and what did he notice?
Answer:
In 1574, an Italian doctor, Girolamo Fabrici, studied the veins in the leg and noticed the presence of valves in them.

Question 26.
What are the very fine blood vessels that connect smallest arteries and veins called?
Answer:
The very fine blood vessels that connect smallest arteries and veins are called capillaries.

Question 27.
Who discovered the capillaries in the wings of bats ?
Answer:
Marcello Malpighi discovered the capillaries (1661) in the wings of bats.

Question 28.
On which day the human heart starts beating during the embryonic development?
Answer:
The human heart starts beating around 21st day during the embryonic development.

Question 29.
What is cardiac cycle ?
Answer:
One contraction and one relaxation of atria and ventricles is called one cardiac cycle.

Question 30.
One cardiac cycle completes in approximately?
Answer:
The whole process of one cardiac cycle completes in approximately in 0.8 seconds.

Question 31.
The cardiac cycle includes?
Answer:
The cardiac cycle includes an active phase systole and a resting phase the diastole of atria and ventricles.

Question 32.
The number of heart beats in Blue Whale?
Answer:
The number of heart beats in Blue Whale are 7 times.

Question 33.
The number of heart beats in the bird Coaltit?
Answer:
The number of heart beats in the bird coaltit are 1200 times.

Question 34.
What is Edema?
Answer:
Edema is the condition in which the lower part of the legs will be swollen due to overnight journey in sitting position without moving legs.

Question 35.
What is single circulation of blood?
Answer:
If blood flows through heart only once in one circulation is called single circulation, e.g: Fish.

Question 36.
What is double circulation of blood?
Answer:
If the blood flows through the heart twice in one circulation is called double circulation, e.g : Frog and man.

Question 37.
What is lymph?
Answer:
Lymph is the substance that contains blood without solid particles.

Question 38.
What is tissue fluid?
Answer:
To supply nutrients to the cells the liquid portion of the blood with nutrients flows out of the capillaries. This is called tissue fluid.

Question 39.
What is serum?
Answer:
The light yellow coloured liquid portion after formation of the blood clot is called serum.

Question 40.
In which organism does protoplasm show Brownian movements?
Answer:
Protoplasm shows Brownian movements in Amoeba.

Question 41.
Which organisms use sea water for transportation?
Answer:
The poriferans/parazoans like sponges use sea water for transportation.

Question 42.
Which takes up the function of digestion and transportation of nutrients to each and every cell of the body in cnidarians?
Answer:
Gastrovascular cavity takes up the function of digestion and transportation of nutrients to each and every cell of the body in cnidarians. e.g: Hydra and Jelly fish.

Question 43.
In which animals is the digestive system highly branched and digested food to all the cells is supplied?
Answer:
The digestive system is highly branched and supplies digested food to all the cells in platyhelminthes.

Question 44.
Which takes up the function of collection and distribution of materials in Nematyhelminthes?
Answer:
The Pseudocoelom takes up the function of collection and distribution of materials in Nematyhelminthes.

Question 45.
What are the first Eucoelomate animals?
Answer:
The Annelids are the first eucoelomate animals.

Question 46.
Which have developed the heart, a pulsative organ to pump the blood?
Answer:
The Arthropods have developed the heart, a pulsative organ to pump the blood.

Question 47.
What is lymphatic system?
Answer:
Lymphatic system is a parallel system to venous system which collects tissue fluid from tissues and transports it to the venous system.

Question 48.
What is open type of circulatory system?
Answer:
The transportation system which supplies nutrients to the tissues directly is called open type of circulatory system, e.g: Arthropods, many molluscs and lower chordates.

Question 49.
What is closed type of circulatory system?
Answer:
The transportation system where the blood takes the responsibility of delivering the materials, which flows in the blood vessels is called closed type of circulatory system, e.g : Annelids, echinoderms, cephalopod molluscs and all the higher animals.

Question 50.
Where do doctors measure blood pressure in human beings?
Answer:
Doctors measure blood pressure in the upper arm artery.

Question 51.
What is the instrument used to measure blood pressure?
Answer:
The instrument used to measure blood pressure is a sphygmomanometer.

Question 52.
What is the normal blood pressure of a human being?
Answer:
The normal blood pressure of a human being is 120/80.

Question 53.
What is Hypertension? (OR)
What is high blood pressure?
Answer:
In some people high blood pressure more than the normal blood pressure of 120/80 is present during rest period. Such a condition is called Hypertension usually called high B.P.

Question 54.
Which vitamin plays an important role in coagulation of blood?
Answer:
Vitamin – K plays an important role in the coagulation of blood.

Question 55.
What is Haemophilia?
Answer:
Due to genetic defect, the blood may not coagulate or clot. This type of defect is called haemophilia.

Question 56.
What is Thalassemia?
Answer:
Thalassemia is a group of inherited blood disorders characterized by mild to severe anaemia caused by haemoglobin deficiency in the red blood cells.

Question 57.
Why is the blood pressure more in arteries than veins?
Answer:
The arteries receives blood directly from the heart hence the pressure is more in arteries than veins.

Question 58.
Why is the wall of left ventricle thicker than that of the right ventricle?
Answer:
The left ventricle pumps blood to more distant parts of the body such as from heart to fingers and toes. Hence the wall of left ventricle is thicker than that of the right ventricle.

Question 59.
How is xylem situated in the root and the stem?
Answer:
In the root the xylem tissue is situated towards the exterior while in the stem it is arranged in bundles towards the center.

Question 60.
Which process plays an important role in the absorption of water by root hairs?
Answer:
Osmosis plays an important role in the absorption of water by root hairs.

Question 61.
What is transpiration?
Answer:
Evaporation of water in the form of water vapour through stomata of leaves is called transpiration.

Question 62.
What are the different types of nutrients required for plant growth?
Answer:
Micronutrients and macronutrients are the different types of nutrients required for plant growth.

Question 63.
Which tissue transports water to all the other parts of the plant?
Answer:
Xylem tissue transports water to all the other parts of the plant.

Question 64.
Which tissue transports food to all the other parts of the plant?
Answer:
Phloem tissue transports food to all the other parts of the plant.

Question 65.
What is the amount of water that an oak tree can transpire per day?
Answer:
The amount of water that oak tree can transpire per day is 900 liters.

Question 66.
How many liters of water does a fully grown maize plant transpire in a week?
Answer:
Fully grown maize plant transpires 15 liters per week.

Question 67.
How does the opening and closing of stomata take place?
Answer:
When guard cells are filled with water, the walls of the cells are pulled away and the pores open up. When the water content is low the walls of guard cells collapse and close the stomata.

Question 68.
The rate of transpiration depends upon?
Answer:
The rate of transpiration depends on temperature, humidity, wind velocity, soil, water content, etc.

Question 69.
How does the transpiration help the leaf of a plant?
Answer:
Transpiration helps to keep the leaf surface at a lower temperature than the surrounding air.

Question 70.
What is translocation?
Answer:
The transport of soluble product of photosynthesis through phloem is known as translocation.

Question 71.
Why are the artery walls very strong and elastic?
Answer:
Because they are carrying blood away from the heart to every cell of the body tissue and are doing with a lot of pressure. So the walls are thick to enable it to do its job and are elastic.

Question 72.
The lumen size is bigger in vein when compared with artery. Why?
Answer:
Veins are generally large in diameter, carry more blood volume and have thinner wall in proportion to their lumen.

Question 73.
What is the function of the Gastrovascular cavity?
Answer:
Digestion and transportation of nutrients to each cell of the body in cnidarians is the function of Gastrovascular cavity.

Question 74.
What is the meaning of the word lymph in Latin?
Answer:
In Latin, lymph means water.

Question 75.
It is advisable to take limited food in journey? Why?
Answer:
The body movements will be less in the journey. So taking little food is good for easy digestion.

Question 76.
It is advised to take low amounts of salt in food? Why?
Answer:
Salt (sodium) levels will be more in accumulated water at the time of edema. If salt is not reduced in food the salt levels increase in blood and cause other problems in the body. Hence it is advised to take low amounts of salt in food.

Question 77.
When do you think that our pulse rate goes up?
Answer:
Our pulse rate goes up after jogging, running, strenuous exercise, during fear, anxiety, etc.

Question 78.
Sometimes barks of the tree damaged more than a half, even though tree is alive. How is this possible?
Answer:
In the root the xylem tissue is situated towards the exterior while in the stem it is arranged in bundles towards the center. Hence if the barks of the tree are damaged more than a half there is no obstruction to flow of water, the tree is alive.

Question 79.
Which animals do great damage particularly to beech and sycamore?
Answer:
Grey squirrels do great damage particularly to beech and sycamore.

Question 80.
Which predators are encouraged by foresters to keep down the population of voles and rabbits that damage plants?
Answer:
Foxes, Badgers, Hawks, Owls are encouraged by foresters to keep down the population of voles and Rabbits that damage plants.

Question 81.
What is Rhesus factor?
Answer:

1. It is an antigen occuring on the red blood cells of many humans (85%) and same other primates known as the rhesus factor.
2. It also plays major role in transfusion.
3. Rhesus factor was first discovered in rhesus monkeys.

10th Class Biology 3rd Lesson Transportation 2 Marks Important Questions and Answers

Question 1.
Using the data collected by you, from internet and other sources, make a report on coagulation of blood.
Answer:
The process of clotting of blood from the blood vessels when a person injured is known as blood coagulation. Blood platelets starts the process of blood coagulation. When the blood flows out, the platelets release an enzyme called “Thrombokinase”. Thrombokinase acts on prothrombin converting it into thrombin.
Thrombin acts on another substance called fibrin that is present in dissolved state converting it into insoluble fibrin. The blood cells entangle in the fibrin fibres forming the clot.

Question 2.
By the information provided by scientist William Harvey, complete the following table.

SI. No.	Vessel Structure / function	Artery	Vein
1.	Thickness of walls (Thick / Thin)
2.	Valves (Present / Absent)
3.	Pressure in the vessels (low / high)
4.	Direction of blood flow (heart to organs / body organs to heart)

Answer:

SI. No.	Vessel Structure / function	Artery	Vein
1.	Thickness of walls (Thick / Thin)	Thick	thin
2.	Valves (Present / Absent)	Absent	Present
3.	Pressure in the vessels (low / high)	high	low
4.	Direction of blood flow (heart to organs body organs to heart)	heart to organs	body organs to heart

Question 3.
How did you prepare a match-stick Stethoscope in your school?
Answer:

1. Take a shirt button.
2. Insert a matchstick into the button.
3. Place it on wrist.
4. We have to observe the movements of the matchstick.

Question 4.
After reading the functions of lymphatic system, what precautions you would suggest to your elders about Edema ?
Answer:

1. Should not sit in the same position for long time.
2. Should move legs frequently.
3. Should sit in a up right position.
4. Take low salt diet.
5. Do exercise regularly.
6. Protect themselves from extreme temperature changes.

Question 5.
What will happen if pulmonary veins are tied with a thread?
Answer:
The pulmonary vein brings oxygenated blood from the lungs and open into left auricle. If the pulmonary veins are tied with a thread the oxygenated blood will not supply to the heart and body parts from the lungs. Hence the person will die because of lack of oxygen.

Question 6.
Suggest some precautions to avoid cardiac problems.
(OR)
What changes would you like to bring in your life style to avoid cardiac problems?
Answer:
I will bring following changes in my lifestyle.

1. Avoid heavy fat food and junk food.
2. Try to spend stress free life as stress leads to cardiac problems.
3. I will do regular physical exercise or work to keep myself fit.
4. Keep away from bad habits like smoking and alcohol consumption.
5. After 40 years, yearly twice I will consult cardiologist.

Question 7.
Read the Para:
Platelets play major role in the coagulation of blood. Whenever the blood flows from the wound, platelets releases the enzyme called Thrombokinase. Thrombokinase acts on another substance present in the blood called prothrombin converting it into thrombin. Thrombin acts on another substance called fibrin that present in the dissolved state converting it into insoluble Fibrin fibers. The blood cells entangle in the Fibrin fibers forming the clot.
Now, answer the following questions:
a) What happens if blood is not coagulated?
Answer:
If blood is not coagulated, it bleeds continuously from the wound, some times it leads to death of a person.

b) Which enzyme helps in the coagulation process?
Answer:
The enzyme thrombokinase helps in coagulation process.

c) How is Thrombin formed?
Answer:
Thrombokinase acts on another substance present in blood called prothrombin converting it into thrombin.

d) What do we call the yellow coloured fluid appear after the formation of the clot?
Answer:
The yellow coloured fluid appear after the formation of the clot is SERUM.

Question 8.
Observe the following table and answer the questions.

Name of the animal	Weight of the body	Weight of the heart	No. of beats / min.
Blue whale	1,50,000 kgs	750 kgs	7
Elephant	3,000 kgs	12-21 kgs	46
Man	60-70 kgs	300 grams	76
Coal Tit Bird	8 grams	0.15 grams	1200

i) What is meant by Cardiac cycle?
Answer:
One contraction and one relaxation of atria and ventricles is called one Cardiac Cycle.

ii) Write relation between the weight of the heart and heart beat.
Answer:
If the heart weight increases the rate of heart beat decreases and if the heart weight is less and the rate of heart beat is more.

Question 9
Look at the following table and answer the questions.

Name of the Student	Systolic Pressure	Diastolic Pressure
Kiran	120	80
Rajesh	160	100

a) Who is healthy person? Why?
b) Who is suffering from hypertension? What are the reasons?
Answer:
a) Kiran is a healthy Person as he has normal blood pressure of 120/80 mm/Hg.
b) Rajesh is suffering from hypertension. Reasons for hypertension are eating foods with high salt, obesity, smoking habits, alcohol consumption, lack of physical exercises and hereditary reasons.

Question 10.
What would happen if transpiration doesn’t occur in plants?
Answer:
i) Transpiration is a process by which plants lose excess of water in the form of water vapour, which in turn returns to environment and comes down as rain. Forests have the highest rainfall due to transpiration.

ii) If plants do not transpire, it affects rainfall.

Question 11.
Neelima conducted an activity on her friends and got the following results.

S.No.	Name	Heart beat at rest/min	Heart beat after jogging / min	Pulse rate at rest / min
1.	Jeevan	72	109	72
2.	Raju	75	110	74
3.	Reshma	73	111	73

i) What is the relation between heart beat and pulse rate?
Answer:
Heart beat rate is equal to pulse rate.

ii) Why is the heart beat rate more after jogging?
Answer:
In the jogging muscles need more oxygen to produce high energy. To supply this oxygen heart beat is increased after jogging.

Question 12.
A person is injured while playing on the ground. Blood is flowing continuously. What might be the reasons?
Answer:
In this case blood is not clotting. Because

1. He may be suffering from ‘Haemophilia’.
2. Blood platelets are less in number.
3. He may suffer from vitamin-K deficiency.
4. Enzyme ‘Thrombokinase’ may not release.

Question 13.
What questions do you pose to your teacher to understand ‘blood clotting’?
Answer:

1. What is coagulation?
2. How does blood coagulate?
3. What are the factors responsible for coagulation?
4. What happens if coagulation occurs in blood vessels?
5. Which substance prevents coagulation of blood in blood vessels?
6. Which vitamin is required for coagulation of blood?
7. What happens if coagulation of blood does not occur when we meet with accidents?
8. Which cells present in blood help in coagulation of blood?

Question 14.
Where are the valves located in human heart? Write their names.
Answer:
Valves present in human heart.

Name of the valve	Location	Allows blood to flow from
1. Tricuspid Valve	Right auriculoventricular septum	Right atrium to right ventricle.
2. Bicuspid Valve (Mitral Valve)	Left auriculoventricular septum.	Left atrium to left ventricle.
3. Pulmonary Valve	At the origin of pulmonary aorta in the right ventricle.	Allows blood to flow from right ventricle into pulmonary aorta.
4. Systemic Valves (Aortic Valves)	At the origin of systemic- aorta in the left ventricle.	Allows blood to flow from left ventricle into the systemic aorta.

Question 15.
What happens if there are no valves in veins?
Answer:

1. If the valves are absent in veins blood will not flow in unidirection and flows backward too.
2. Blood will not be supplied to heart properly.
3. Bulging of veins may takes place.

Question 16.
Which items do you take into consideration to explain the differences of arteries and veins?
Answer:
I would like to consider the following items to explain the difference between arteries and veins. They are thickness of walls, valves, capacity to retain shape when blood is absent, direction of blood flow, pressure in the vessels, type of blood transported, type of blood carried by pulmonary artery and type of blood carried by pulmonary vein.

Question 17.
When you know the heart pumping method is circulatory system, which issue do you remember particularly? What’s the reason for that?
Answer:
The heart beats faster during and after an exercise remembered by me. Because at that time our body needs more energy under these conditions. The faster breathing of heart pumps blood more rapidly to the body organs which supplies more oxygen to the body cells for rapid respiration to produce more energy. That is a great job for heart muscle.

Question 18.
Classify different types of blood vessels in humans. On what bases do you classify blood vessels?
Answer:

1. There are three types of blood vessels called arteries, veins and capillaries present in humans.
2. These blood vessels are classified on the basis of thickness of walls, valves, capacity to retain shape when blood is absent, direction of blood flow, pressure in the vessel, type of blood transported, type of blood carried by pulmonary artery or vein.

Question 19.
Anil fell down while going to school, got knee injury, started bleeding. After sometime he wondered on seeing blood clot? Why did blood clot?
Answer:
Blood clotting normally occurs when there is damage to blood vessel. Platelets immediately begin to combine to the cut edges of the vessel and release chemicals to attract even more platelets. A platelet clot is formed and the external bleeding stops.

Question 20.
How is the human heart protected from shocks or injuries?
Answer:
Protection of human heart:

1. Heart in human beings is protected in different ways.
2. It is enclosed in a double layered, transparent thin membrane called pericardium.
3. The space between the inner and outer layers is called pericardial space.
4. This space is filled with a fluid called pericardial fluid.
5. Pericardium and pericardial fluid protect the heart from physical shocks.
6. It is also protected by ribcage or chest cavity.

Question 21.
Describe the blood vessels that carry away blood from human heart.
Answer:

1. The rigid vessels called arteries which originate from the heart supply blood to various organs in the body.
2. From the upper part of the left ventricle a thick blood vessel called Systemic Aorta arises. It supplies oxygenated blood to the body parts.
3. From the upper part of the right ventricle pulmonary artery arises. It supplies deoxygenated blood to the lungs.
4. A pair of coronary arteries (vessels) carry oxygenated blood to the muscles of heart.

Question 22.
What is a mitral valve? What is its function?
Answer:

1. Mitral valve: The valve present between left atrium and vertricle is known as mitral valve.
2. Function: It allows blood to flow from left atrium to left ventricle. It also known as bicuspid valve.

Question 23.
Describe the external features of heart.
Answer:

1. Heart is a hollow organ. It is situated slightly towards left side in the middle of the chest cavity.
2. It is made up of cardiac muscle.
3. It is pear shaped wider at the anterior and narrower at the posterior end.
4. It is protected by ribcage and vertebral column.
5. Generally it is the size of the one’s fist.

Question 24.
What are the differences between right ventricle and left ventricle?
Answer:

Right ventricle	Left ventricle
1. Smaller in size.	1. Larger in size.
2. Pulmonary artery takes its origin.	2. Aorta takes its origin.
3. Receives deoxygenated blood from right auricle.	3. Receives oxygenated blood from left auricle.
4. Pumps deoxygenated blood to lungs.	4. Pumps oxygenated blood to all parts of the body except lungs.
5. Tricuspid valve guards the auriculo – ventricular aperture.	5. Bicuspid valve (mitral) guards the left auriculo – ventricular aperture.

Question 25.
How can Thalassemia major be treated?
Answer:

1. Thalassemia major should be diagnosed as early as possible in order to prevent growth restriction, thin bones and infections in the first year of life.
2. If Hb is less than 70% or the child shows signs of poor growth and development.
3. Regular transfusion is the treatment of choice.
4. This can usually be achieved by carrying out transfusions of concentrated red blood cells at intervals of every three to four weeks.
5. Today Thalassemia major can be cured by stem cell transplantation.

Question 26.
Why is double circulation necessary in human beings? Or Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer:

1. In humans the right side and left side of the human heart is useful to keep deoxygenated and oxygenated blood from mixing.
2. The separation of oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body.
3. It is useful in case of humans which constantly require energy to maintain their body temperature constant.

27. In some people blood does not coagulate. Give the reasons for it.
(OR)
What is Haemophilia? What are the causes for it?
Answer:

1. Normally the blood that comes out from a wound clots in 3 – 6 minutes. But in some people due to vitamin K deficiency it takes more time to clot.
2. Due to genetic defect blood may not coagulate. This type of defect is called Haemophilia.
3. Haemophilia is a common disorder in the children who have born from the marriages between very close relatives.

10th Class Biology 3rd Lesson Transportation 4 Marks Important Questions and Answers

Question 1.
What is coagulation of blood ? Explain the process of coagulation in brief.
(OR)
Collect information from internet and other sources about blood clotting and prepare a note on it.
Answer:
When the blood vessel is injured, the platelets collect at the site of the injury and form a clot and prevents further loss of blood. This is known as coagulation of blood. Process of Coagulation:

1. When the blood flows out from injuries, the platelets release an enzyme called thrombokinase.
2. Thrombokinase acts on another substance present in the blood called prothrombin converting it into thrombin.
3. Thrombin acts on another substance called fibrin, that is present in dissolved state converting it into insoluble fibrin.
4. The blood cells entangle in the fibrin fibers forming the clot.
5. The fibrin fibers are attached to the edges of the wound and pull them together.

Question 2.
B₁, B₂, B₃, A, C, D, E, K are the symbols of vitamins. Classify these vitamins based on solubility and diseases due to vitamins deficiency.

S.No.	Water soluble	Disease due to deficiency	Fat solube	Disease due to deficiency

Answer:

S.No.	Water soluble	Disease due to deficiency	Fat solube	Disease due to deficiency
I	B1	Beri – Beri	A	Eye, Skin disease
2	B2	Glossitis	D	Rickets
3	B3	Pellagra	E	Fertility disorders
4	Vit C	Scurvy	K	Delay in Blood clotting

Question 3.
Ramu got injured while playing Kabaddi. His blood clotted within 6 minutes. Write the procedure involved in it.
Answer:

When the blood flows out from injuries, the platelets release an enzyme called thrombokinase.
2) Thrombokinase acts on inactive prothrombin and converts into thrombin.
3) Thrombin converts the soluble fibrinogen into insoluble fibrine fibers.
4) The blood cells entangle in the fibrin fibers forming the clot.
(or)

Question 4.
Read the para:

In the heart, superior vena cava and inferior vena cava opened into right atrium. The pulmonary veins bring blood from the lungs and open into left atrium. The valve present between the right atrium and right ventricle is referred as ‘Tricuspid valve ’. The valve present between the left atrium and left ventricle is refferred as Bicuspid valve. A major blood vessel that originate from right ventricle is Pulmonary Aorta. The valves present at the region of Pulmonary Aorta are called pulmonary valves. A major blood vessel originates from left ventricle is Systemic Aorta. The valves present at the region of Systemic Aorta are called systemic valves.

Now, fill the table with the above information.

Name of the valve	Location	Way of blood flow	Nature of the blood oxygenated / deoxygenated
a. Tricuspid Valve
b. Bicuspid Valve
c. Pulmonary Valves
d. Systemic Valves

Answer:

Name of the valve	Location	Way of blood flow	Nature of the blood oxygenated / deoxygenated
a. Tricuspid Valve	Right auriculo ventricular septum	Right atrium to right ventricle	Deoxygenated blood
b. Bicuspid Valve	Left auriculo ventricular septum	Left atrium to left ventricle	Oxygenated blood
c. Pulmonary Valve	At the origin of pulmonary aorta in the right ventricle.	From right ventricle into pulmonary aorta	Deoxygenated blood
d. Systemic Valves	At the origin of systemic aorta	From left ventricle into the systemic aorta	Oxygenated blood

Question 5.
Study the given paragraph and answer the questions.

When you cut yourself the blood flows out of the wound for only a short time. Then the cut is filled with a reddish solid material. This solid is called a blood clot. When blood flows,out, the plate lets release an enzyme called thrombokinase. Thrombokinase acts on another substance present in the blood called pro – thrombin converting it in to thrombin. Thrombin acts on another substance called fibrinogen that is present in dissolved state converting it in to insoluble fibrin. The blood cells entangle in the fibrin fibers forming the clot.

A) Which blood cells are helpful in blood coagulation?
B) Which enzyme is responsible for blood coagulation? When is it released?
C) How does soluble fibrinogen in blood convert into insoluble fibrin fibers?
D) What will happen, if blood doesn’t coagulate when wound occurs?
Answer:
A) Blood platelets
B) Thrombokinase is responsible for blood coagulation. When the blood flows out the platelets release this enzyme thrombokinase.
C) Thrombin converts fibrinogen in blood into insoluble fibrin.
D) Blood bleeding from the injuries occurs continuously leads to death.

Question 6.
i) Label the parts of heart in the diagram below:
ii) Which blood vessel brings deoxygenated blood from all parts of the body?
iii) Which chamber(s) of the heart have more thick walls? Why?
Answer:
i)

1. Artery to left arm
2. Pulmonary artery
3. Left atriu
4. Left artrioventricular valve
5. Inferior vena cava
6. Right atrio – ventricular valve
7. Right atrium
8. Superior vena cava

ii) Superior vena cava / Inferior vena cava
iii) Ventricles; to pump blood.

Question 7.
Describe the internal structure of heart with a neat labelled diagram.
(OR)
What is called pumping station in human body? Explain its structure with suitable diagram.
Answer:

1. Heart is called pumping station in human body.
2. Internally heart is divided into four parts by grooves.
3. Two upper parts are called atria, and two lower parts are called ventricles.
4. The two atria are separated from each by inter-atriolar septum and the right and left ventricles are separated from each other by inter-ventricular septum.
5. The inter-atriolar septum and inter-ventricular septum prevent mixing of deoxygenated blood in the right side of the heart with oxygenated blood in the left side of the heart.
6. The walls of the ventricles are relatively thicker than atrial walls.
7. The largest artery is the aorta which arises from the left ventricle supplies blood to all the body parts except lungs.
8. Pulmonary artery that arises from the right ventricle carries deoxygenated blood to lungs.
9. The right atrium and right ventricle are connected to each other by right atrioventricular aperture.
   
10. The left atrium and left ventricle are connected to each other by left atrioventricular aperture.
11. Tricuspid valve guards the right auriculoventricular aperture and mitral valve or bicuspid valve guards the left atrioventricular aperture.
12. Blood from the anterior parts of the body is collected by superior venacava which opens into right atrium.
13. Blood from the posterior parts of the body is collected by inferior venacava or post caval vein which also opens into right atrium.
14. Coronary arteries supply blood to the muscles of the heart whereas coronary veins collect blood from the heart. It also opens into right atrium.

Question 8.
Write about the valves, their positions, their functions in human heart. How many blood vessels are attached to heart? Write about their positions and functions.
Answer:
Valves and their positions in Human Heart:

1. The valve present in between right atrium and right ventricle is Tricuspid valve.
2. The valve present in between left atrium and left ventricle is Bicuspid valve.
3. The valve present at the region of pulmonary arota is called Pulmonary valves.
4. The valves present at the region of systemic arota is called systemic valves.

Blood vessels attached to the heart, their positions and functions:

1. The blood vessels found in the walls of the heart are coronary vessels which supply blood to muscles of the heart.
2. From the upper part of the left ventricle aorta arises it supplies oxygenated blood to the body parts.
3. From the upper part of the right ventricle pulmonary artery arises which supplies deoxygenated blood to the lungs.
4. The vein which is right side of the heart is superior venacava.
5. The vein which is coming from the posterior part of the heart is inferior venacava which collects blood from posterior part of the body.

Question 9.
Read the table and answer the following questions.

S.No.	Name of the Phylum	Type of transport system
1.	Cnidarians	Gastro vascular cavity
2.	Platyhelminthes	Digestive system
3.	Nematyhelminthes	Pseudocoelom
4.	Annelida	Blood vessels
5.	Arthropoda	Open circulatory system

i) In which phylum, blood vessels are first formed?
Answer:
Blood vessels first formed in phylum annelida.

ii) In which phylum, organisms have haemoglobin in their blood?
Answer:
Organisms in phylum annelida have haemoglobin in plasma of blood,

iii) In which phylum, digestive system helps in transportation?
Answer:
The digestive system in the phylum cnidarian helps in transportation,

iv) Why do arthropods have open circulatory system?
Answer:
In arthropods blood vessels are absent, sinuses are present. So they have open circulatory system.

Question 10.
Write a short note on Human Lymphatic System and its functions.
Answer:

1. Lymphatic system consists of lymph capillaries, lymph vessels, lymph nodes and lymph glands.
2. To supply nutrients to the cells (tissues), the liquid portion of the blood with nutrients flows out of the capillaries. This is called tissue fluid.
3. To transport the tissue fluid into the main blood stream, a separate system called lymphatic system is present.
4. Lymph is the vital link between blood and tissues by which essential substances pass from blood to cells and excretory products from cells to blood.
5. Lymph is the substance that contains blood without solid particles.
6. From intercellular spaces, lymph goes into lymphatic capillaries.
7. Lymphatic capillaries join to form large lymph vessels which finally open into larger veins.
8. Lymph flows only in one direction, that is from tissues to heart through veins.
   Functions of Lymph:
   a) Lymph carries digested and absorbed fats from small intestine to different tissues of the body.
   b) It helps in removing waste materials from the cells in the body to drain into blood.
   c) Lymph protects cells in the tissues from infection.

Question 11.
Explain the process of coagulation of blood.
Answer:

1. When the blood flows out from injuries, the platelets release an enzyme called thrombokinase.
2. Thrombokinase acts on another substance present in the blood called prothrombin converting it into thrombin.
3. Thrombin acts on another substance called fibrin, that is present in dissolved state converting it into insoluble fibrin.
4. The blood cells entangle in the fibrin fibers forming the clot.
5. The fibrin fibers are attached to the edges of the wound and pull them together.

Question 12.
Observe the given diagram. Which type of cardiac cycle does it indicate? Explain the process that happens here.
Answer:

1. It indicates double circuit circulation. It includes pulmonary circulation and systemic circulation.
2. Here blood flows through the heart twice for completing one circulation. Hence it is called double circulation.
3. In this circuit deoxygenated blood from organs of body is collected into the right auricle and then sent into right ventricle. From right ventricle blood is pumped to the lungs. In the lungs blood is oxygenated and is returned to the left auricle by pulmonary vein. This circulation is known as pulmonary circulation.
4. In systemic circulation the oxygenated blood from the left auricle is pumped into the left ventricle. From the left ventricle blood is pumped into the systemic aorta. This aorta supplies blood to various organs of the body.

Question 13.
In human body “A” is a pumping organ. From lungs blood vessel “B” with oxygen¬ated blood enters upper “C” part of left chamber of the organ. When “C” chamber contracts blood flows into “D” lower left chamber. “D” chamber contracts blood is pumped to all parts of the body except lungs through blood vessel E. Deoxygen¬ated blood from body parts is collected by blood vessel “F’ and opens upper “G” right chamber. This chamber contracts blood flows “H” lower chamber. Lastly “H” contracts De-oxygenated blood sent to lungs by blood vessel “I”.
a) “A” represents what organ?
b) (i) B (ii) E (iii) F and (iv) I are what blood vessels? Write their names.
c) (i) C (ii) D are what chambers?
d) (i) G (ii) H are what chambers? Write their names.
Answer:
a) Heart
b) i) B – Pulmonary vein
ii) E – Systemic aorta
iii) F – Superior or Inferior venacava
iv) I – Pulmonary artery
c) i) C – Left atrium
ii) D – Left ventricle
d) i) G – Right atrium
ii) H – Right ventricle

Question 14.
Which blood vessels bring blood to human heart and from where?
Answer:

1. There are three large veins that bring blood to heart from all the body parts.
2. From upper parts of the body (from head and neck) blood is collected by superior venacava.
3. The inferior venacava brings deoxygenated blood from lower parts of the body like abdomen, hands and legs. These caval veins open into right auricle.
4. The third vein called pulmonary vein brings oxygenated blood from lungs and open into left ventricle.
5. In addition to these, veins called coronary veins bring deoxygenated blood from the walls of the heart. They also open into right auricle.

Question 15.
Give an account of valves in the human heart. (OR)
Write about different valves present in human heart and their uses.
Answer:

1. Heart has valves which allow the flow of blood only in one direction and prevents its flow in backward direction. Valves are held in position by tough connective tissue called chordaetendinae.
2. Right auriculo – ventricular aperture is controlled by a tricuspid valve which allows the blood flow from right auricle to right ventricle.
3. Left auriculo – ventricular aperture is provided with bicuspid valve which controls the blood flow from left auricle to left ventricle.
4. At the origin of pulmonary aorta in the right ventricle three half moon shaped or semilunar valves present which allow the blood to flow from right ventricle into pulmonary aorta.
5. At the origin of systemic aorta in the left ventricle there are three semilunar aortic valves which allow the blood flow from left ventricle into the aorta.

Question 16.
What is pulmonary circuit ? Explain it with the help of a block diagram.
Answer:

1. In pulmonary circulation the deoxygenated blood collected by superior and inferior venacava enters right auricle.
2. From right auricle the deoxygenated blood enters right ventricle from there it send to the lungs by pulmonary artery.
3. From lungs pulmonary vein carries oxygenated blood into left auricle. From here blood enters into left ventricle.
   

Question 17.
What is systemic circuit? Explain it with the help of a block diagram.
Answer:

1. In systemic circulation oxygenated blood from left atrium is pumped into left ventricle.
2. From left ventricle the blood is carried to different parts of the body through systemic Aorta.
3. The deoxygenated blood from all the body parts is collected into right auricle through inferior and Superior Venacava.
   

Question 18.
Complete the following table with the details of arteries and veins.

Blood vessels	Draw figure	Thickness of the wall	Layers of the wall	Lumen size	Capacity to retain the shape

Answer:

Question 19.
How did multicellular animals solve their problem of transport of substances?
(OR)
Write about the evolution we see in the transport system of multicellular animals.
Answer:

1. Early in the evolution, multicellular animals have solved their problem of transport by dissolving majority of the required substances in water and then transporting to various body parts. Ex: Sponges to Heimenthes.
2. Later on the evolution, special fluids like blood and lymph have been developed for the transport of substances within the body. Ex: Insects.
3. In primitive animals, necessary force for transport of these fluids was given by contraction and relaxation of body muscles. These fluids were circulated with in the body cavity. Ex: Earthworm.
4. Later on evolution, for circulation of fluids a closed circulatory system was developed. This consists of heart, blood vessels and blood. Ex: Amphibians, reptiles, aves and mammals.

Question 20.
What is blood pressure? How is it measured?
Answer:

1. The pressure with which the blood flows in the blood vessels is known as blood pressure.
2. Blood pressure is measured in the upper artery.
3. There are two pressure readings.
4. One measures the strongest pressure during the time blood is forced out of the ventricles. This is called systolic pressure.
5. For a healthy young adult it will be 120 mm of Hg.
6. The second reading is taken during the rest period, as the ventricles refills with blood. This is called diastolic pressure.
7. The diastolic pressure will be 80 mm of Hg.
8. Doctors measure the blood pressure with a device called sphygmomanometer.

Question 21.
How do you prove that transpiration is done through stomata of a leaf? (OR) Describe an experiment to show that water is lost from the stomata of leaf.
Answer:
Aim: To prove that transpiration is done through stomata present in the leaves.
Required material: A healthy potted plant, a polythene cover, water.
Procedure: Take a well watered plant. Tie a polythene cover to one of its small branch and keep it in the sunlight. After sometime observe the inner sides of the polythene cover.
Observation: It is observed that the inner sides of polythene cover is moist with water drops.
Inference: The excess of water from the plant evaporates through stomata of leaves into the atmosphere. This process is called Transpiration.

Question 22.
Explain the process of absorption of water by the root hair and movement of water in xylem.
Answer:

1. The soil water is an extremely dilute solution of salts, more dilute than that of the cell sap in the root hair.
2. Therefore water will pass into the vacuole of the root hair by osmosis.
3. The entry of water dilutes the contents of the root hair vacuole so that it becomes weaker than its neighbour.
4. Therefore water passes into the neighbouring cell which in turn becomes diluted, finally water enters the xylem vessels.
5. As there are vast numbers of root hairs and root cells involved, a pressure in the xylem vessels develops which forces the water upwards.
6. This total pressure is known as root pressure which is responsible for movement of water in xylem.
7. The water which passed into the xylem vessels forms a continuous system of tubes through root and stem into the leaves.
8. The evaporation of water creates the main pull from above root pressure gives a variable and minor push from below.

Question 23.
Explain the process of transport of mineral salts and water in plants.
(OR)
Explain how root pressure and transpiration pull help in the transport of mineral salts and water in plants.
Answer:

1. Xylem tissue transports water and mineral salts in plants.
2. Xylem vessels and tracheids of root, stem and leaves are interconnected to form a continuous system of water and minerals conducting channels to each part of the plant.
3. The cells of root hair present in the soil absorb water from the soil by osmosis.
4. The entry of water dilutes the contents of the root hair vacuole so that it becomes weaker than its neighbour.
5. Therefore water passes into the neighbouring cell which in turn becomes diluted, finally water enters the xylem vessel.
6. This creates a column of water that is steadily pushed upward, called root pressure.
7. Root pressure is not enough to push water and dissolved minerals to leaves in the tall trees.
8. There is a continuous loss of water through stomata of the leaves in the form of water vapour. This process is called transpiration.
9. The water lost due to transpiration is taken up from the xylem vessels and tracheids in the leaves.
10. This loss of water during transpiration creates a suction pressure which pulls water from the xylem cells of roots.
11. This results in enhanced absorption and upward movement of water and dissolved minerals from roots to the leaves due to transpiration.
12. At night when stomata are closed root pressure has an effect on transportation of water.
13. Transpiration pull is the major force in the movement of water and dissolved minerals in the xylem during daytime.

Question 24.
Write an experiment to illustrate the conduction of sugars by phloem.
(OR)
How are sugars conducted by phloem in plants?
Answer:

1. Experiments to illustrate the conduction of sugars by the phloem have been done by removing a ring of bark from a shoot to expose the wood.
2. Remove all tissues from the cambium outwards including the phloem.
3. After a few days, when the tissues above and below the ring were analyzed.
   
4. It was shown that food had accumulated above the ring but was not present below it.
5. If it is left for sometime, the stem increases in thickness immediately above the ring, but no growth occurred below it.
6. So, any damage to the phloem all around the stem will prevent food from passing down to the roots and the tree will eventually die.

Question 25.
Write about the changes in the evolution of transport system in animals.
Answer:

1. In Amoeba due to Brownian movements nutrients and oxygen are distributed throughout the protoplasm equally.
2. The parazones like sponges use sea water for transportation. Sponges create their own currents by beating of flagella that are present in their body.
3. Cnidarians developed blind sac like gastro vascular cavity, which has taken up the function of digestion and transportation of nutrients, e.g.: Hydra and jelly fish.
4. In platyhelmenthes, the digestive system supplies digested food to all the cells directly, excretory system collects wastes from each cell individually.
5. In animals belonging to Nematyhelmenthes the pseudocoelom has taken up the function of collection and distribution of materials.
6. In Annelids, animals have developed a pulsative vessel to move the fluid and the transporting medium is blood.
7. In Arthropods have developed a pulsative organ to pump the blood. The blood flows in the tissues, directly supplying the nutrients to the tissues.
8. Transportation system which supplies nutrients to the tissues directly is called open type of circulatory system, e.g. : Arthropods, many molluscs and lower chordates.
9. The other type of transportation system where the blood takes the responsibility of delivering the materials, which flows in the blood vessels.
10. Such type of closed circulatory system is present in annelids, echinoderms, cephalopod molluscs and all the higher animals.

Question 26.
Briefly explain about Thalassemia disease.
(OR)
What is thalassemia disease ? What is the main cause for it?
Answer:

1. Thalassemia is a group of inherited blood disorders characterized by mild to severe anaemia caused by haemoglobin deficiency in the red blood cells.
2. In individuals with thalassemia, the production of the oxygen carrying blood pigment haemoglobin is abnormally low.
3. There are two main types of thalassemia: alpha thalassemia and beta thalassemia.
4. In each variant a different part of the haemoglobin is defective.
5. Individuals with mild thalassemia may have symptoms such as anaemia, enlarged liver and spleen; increased susceptibility, slow growth, thin and brittle bones and heart failure.

Question 27.
What are the facts known about Thalassemia?
Answer:

1. Thalassemia is a serious inherited Blood disorder.
2. 4.5% of world population (250 million) suffering with Thalassemia minor.
3. There are over 35 million Indians are carriers of the abnormal Gene for Thalassemia.
4. It is estimated that about 1,00,000 infants are born with major Haemoglobinopathies every year in the world.
5. 10,000 – 12,000 Thalassemic children are born every year in our country.
6. Survival depends upon repeated blood transfusion and costly medicines.
7. Thalassemia can be prevented by awareness, pre marital or pre conceptual screening followed by ante-natal diagnosis is required.

Question 28.
What is the effect of Rhesus factor in childrens if Rh⁺ person marries Rh^– woman?
Answer:

1. If a Rh⁺ man marries a Rh^– woman, some of the children are likely to be RlT.
2. If a child is Rh⁺ some of its blood will leak into its mother’s circulation and cause antibodies to form in her blood.
3. If the mother has more children the amount of antibodies in her blood often increases with each pregnancy, and in some instances the antibodies in her blood may pass into the baby’s blood in sufficient quantities to produce very serious anaemia and even death.
4. When such cases occur, the baby is given a complete transfusion soon after birth sp that the baby’s blood is replaced by blood containing no antibodies to the rhesus factor.

Question 29.
What are the components of the circulatory system in human beings? What are their functions?
Answer:

1. The circulatory system or transport system in human beings consists of heart, blood and blood vessels.
2. Heart is a pumping organ to push blood around the body. It receives deoxygenated blood from body organs and pump it to lungs for oxygenation.
3. Heart receives oxygenated blood from lungs and sends it to different body parts.
4. Blood is a fluid connective tissue consists of a fluid medium known as plasma in which white blood cells, red blood cells and platelets are suspended.
5. Blood transports food, carbondioxide and nitrogenous wastes in dissolved form.
6. Red blood cells transports oxygen.
7. Platelets present in blood help in coagulation of blood.
8. Blood pushed by the heart flows in blood vessels called arteries and also comes back to the heart in the blood vessels called veins.

Question 30.
Draw T.S. of flow of blood in arteries and veins. Write flow of blood in between them.
(OR)
Write the differences between T.S. of artery, T.S. of vein and T.S. of blood capillary.
Answer:

1. In arteries, oxygenated blood flows. Arteries supply oxygenated blood to all body parts except lungs. Pulmonary artery supplies deoxygenated blood from right ventricle to lungs.
2. Veins collects deoxygenated blood from all body parts into the right atrium. Pulmonary vein brings oxygenated blood from lungs into left atrium.
3. Blood capillaries are the microscopic vessels that connect smallest arteries and veins.

Question 31.
What was the classical experiment conducted by William Harvey to demonstrate movement of blood in veins ?
(OR)
How do you repeat the classical experiment to demonstrate the movement of blood in veins?
Answer:

1. In early 17th century William Harvey conducted an experiment to demonstrate the movement of blood in veins.
2. Tie a tornquit just above the elbow of a person, whose blood vessels are prominent in the hand.
3. Ask that person to hold the fist with a piece of cloth rolled in the hand. Now the blood vessels can be seen more prominently.
4. Find undivided blood vessel, where we have to work for the next few minutes.
5. At the end of the vessel farthest from the elbow apply steady pressure, so as to close its cavity.
6. Now apply pressure from elbow towards the palm slowly and observe the changes in the blood vessels.
   

Question 32.
What are the structural and functional differences of arteries, veins and capillaries?
Answer:

1. The walls of arteries are made up of muscle fibers and are elastic. When the blood enters with a pressure into the arteries then walls will stretch and this enables the arteries to withstand the increase in the pressure without bursting.
2. Veins are closer to the skin and contain valves. They are made of connective tissue called Tunica adventitia or Tunica externa. Middle layer has bands of smooth muscle called Tunica media. Generally veins are thin, lined internally with endothelial cells Tunica intina.
3. Blood capillaries are microscopic vessels made of single layer of cells. They allow diffusion of various substances. They establish continuity between arterioles and venules. Capillaries is the Latin word which means “hair” because they were as thin as the finest of hairs.
   

Question 33.
What is the cardiac cycle? Explain it with the help of a diagram.
(OR)
Draw a diagram of different stages of systole and diastole. Explain.
Answer:
One contraction and one relaxation of atria and ventricles is called one cardiac cycle.

1. We start with imagination that all the four chambers of the heart are in relaxed state.
2. Blood from venecava and pulmonary veins enters the right and left atria respectively.
3. Now the atria contract and forcing the blood to enter into the ventricles.
4. On ventricular contraction due to pressure the blood moves into the aorta and pulmonary artery.
5. When the valves between the atria and ventricles are closed we can hear the sharp sound of the heart lub.
6. When the ventricles start relaxing, the pressure in the ventricles is reduced. The blood which has entered the arteries tries to come back into the ventricles. The valves which are present in the blood vessels are closed to prevent backward flow of blood into the ventricles.
7. Now we can listen to a dull sound of the heart dub. The atria filled up with blood and are ready to pump them into the ventricles.
8. The sequential events in the heart which are cyclically repeated are called cardiac cycle. It includes an active phase systole and a resting phase the diastole of atria and ventricles.
   

Question 34.
What is hypertension? How is it caused? Mention the preventive steps to be taken.
Answer:

1. Blood flows in the blood vessels with a specific pressure called Blood Pressure (B.P.) In healthy individuals, the normal B.P. is 120/80.
2. The numerator (120) represents Systolic pressure and the denominator (80) represents Diastolic pressure.
3. Blood pressure is measured by the doctors by an instrument called SPHYGMOMANOMETER.
   
4. However in some people blood pressure is very high more than normal B.P. This condition is called Hypertension.
5. One of the reasons for hypertension is the blocking of arteries by cholesterol. Constant stress and strain for a long time, improper functioning of kidneys, smoking and alcohol consumption are the reasons for high B.P.
6. Hypertension can be prevented by diet control moderate exercise, avoiding stress and strain, avoiding
   alcohol consumption and smoking.

AP State Board Syllabus AP SSC 10th Class Biology Important Questions Chapter 2 Respiration.

AP State Syllabus SSC 10th Class Biology Important Questions 2nd Lesson Respiration

10th Class Biology 2nd Lesson Respiration 1 Mark Important Questions and Answers

Question 1.
What are the end products of Aerobic and Anaerobic Respirations?
Answer:
End products of aerobic respiration: Carbon dioxide, Water, Energy
End products of anaerobic respiration: Ethanol / Lactic acid, Carbon dioxide, Energy

Question 2.
In which organisms, blood does not supply the Oxygen?
Answer:
Arthropoda organisms (or) Insects (OR) Tracheal respiratory Organisms.

Question 3.
Hari said that stem also respires along with leaves. How do you support him?
Answer:
Lenticels on stem also help in gaseous exchange in some woody plants along with stomata.

Question 4.
Arrange the apparatus as above and heat the glucose. What will happen to lime water when glucose burns?
Answer:
Lime water turns milky due to carbon dioxide (CO₂).

Question 5.
What is the role of mitochondria in anaerobic respiration?
Answer:
The release of energy from glucose in the presence of oxygen occurs in mitochondria. In anaerobic respiration, as oxygen is absent, mitochondria have no role in respiration.

Question 6.
Fermented idli, dosa produce smell. Name the microorganism responsible for producing such smell.
Answer:
Yeast is responsible for producing such smell in fermented idli, dosa.

Question 7.
In what compound, the energy released during the breakdown of glucose is stored?
Answer:
“ATP” (Adenosine Triphosphate).

Question 8.
Label a and b in the given diagram.

Answer:
(a) Matrix, (b) Cristae.

Question 9.
Name chemical substance produced in human muscles during Anaerobic respiration.
Answer:
Lactic acid is produced in human muscles during Anaerobic respiration.

Question 10.
Why is Diazene Green solution added to the Glucose solution in anaerobic respiration experiment?
Answer:
Diazene Green solution is added to the Glucose solution in anaerobic respiration experiment to check the presence of oxygen in glucose solution.

Question 11.
Name the food material on which trypsin acts and name the end products.
Answer:
i) protein ii) end products – peptones.

Question 12.
“Respiration is the energy releasing process.” Write your opinion on this statement.
Answer:
The given statement is absolutely correct. We respire to use the oxygen to oxidise our food and release energy. This is similar like burning but a slower process. With the help of respiratory enzymes, energy released can be stored in the form of ATP for later use.

Question 13.
Identify the figure.

Answer:
Aerial roots in Mangrove plants.

Question 14.
Can we say that combustion and respiration are almost same actions? What evidences do you have for this?
Answer:

1. In both these processes sugar is converted to carbon dioxide and water.
2. Both these processes require oxygen.
3. Both combustion and respiration releases energy.

Question 15.
What is the role of epiglottis in respiration and swallowing food?
Answer:
The epiglottis is a flexible flap at the superior end of the pharynx in the throat. Epiglot¬tis acts as a lid over glottis and prevents food from entering into larynx. Air from pharynx enters the larynx while food enters into oesophagus.

Question 16.
What is the function of haemoglobin?
Answer:
During respiration haemoglobin carries oxygen to the cells and CO, from cells to lungs.

Question 17.
What is respiration?
Answer:
Respiration is the process by which food is broken down to release energy.

Question 18.
What does the word respiration mean in Latin?
Answer:
In Latin the word respiration means “to breathe”.

Question 19.
Who did comprehensive work on properties of gases, their exchange and respiration?
Answer:
Lavoisier and Priestly.

Question 20.
What was the gas liberated on heating powdered charcoal in a bell jar?
Answer:
It was fixed air. In those days carbon dioxide was known as fixed air.

Question 21.
What is oxygen debt?
Answer:
It is the inadequate supply of oxygen when we undertake strenuous exercise.

Question 22.
What is vitiated air?
Answer:
It is the term used then to show air from which the component needed for burning had been removed.

Question 23.
What is the total lung capacity of human being?
Answer:
The total lung capacity of human being is nearly 5800 ml.

Question 24.
Who was the renowned chemist who wrote a textbook of Human Physiology?
Answer:
John Daper was the renowned chemist who wrote a textbook of Human Physiology.

Question 25.
What happens when air passes through nasal cavities?
Answer:

1. Air is filtered in nasal cavity by mucus lining and the hairs growing from its sides, remove some of the tiny particles of dirt in the air.
2. The temperature of the air is brought close to that of the body.

Question 26.
What is the function of epiglottis?
Answer:
Epiglottis controls the movement of air and food towards their respective passages.

Question 27.
What is breathing?
Answer:

1. Breathing is the process of inhaling and exhaling.
2. The mechanism by which organisms obtain oxygen from the environment and release CO₂ is called breathing.

Question 28.
What are pleura?
Answer:
Pleura are the two membranes that protect lungs from injury.

Question 29.
What is the concentration of oxygen at a height of 13 km from the sea level?
Answer:
At a height of 13 km above sea level the concentration of oxygen is much lower about one-fifth as great as at sea level.

Question 30.
What is cellular respiration?
Answer:
Oxidation of glucose or fatty acids takes place in the cells releasing energy. Hence this process is known as cellular respiration.

Question 31.
Where does aerobic respiration occur in eukaryotic cells?
Answer:
Aerobic respiration occur in cytoplasm and mitochondria of eukaryotic cells.

Question 32.
What is Glycolysis?
Answer:
It is the first stage of respiration. In this breakdown of glucose molecule into two molecules of 3 carbon compound called pyruvic acid or pyruvate releasing energy.

Question 33.
What is the fate of pyruvate in the absence of oxygen in animals?
Answer:
In the absence of oxygen pyruvate will be converted to lactic acid and release small amount of energy in animals.

Question 34.
In which type of respiration pyruvate is converted into carbon dioxide and water?
Answer:
In aerobic respiration pyruvate is converted into carbon dioxide and water.

Question 35.
What is the main reason for feeling pain in muscles after strenuous exercise?
Answer:
Due to the anaerobic respiration in muscles large amounts of lactic acid is accumulated and this results in muscular pains.

Question 36.
What is fermentation?
Answer:
In the absence of oxygen, yeast cells convert pyruvic acid to ethanol. This process is called fermentation.

Question 37.
What is the method used to separate ethanol from the yeast glucose mixture in anaerobic respiration?
Answer:
The method used to separate ethanol from the yeast glucose mixture in anaerobic respiration is fractional distillation.

Question 38.
In which organisms does exchange of gases take place through diffusion?
Answer:
In Amoeba, hydra and planarians exchange of gases takes place through diffusion.

Question 39.
In tracheal respiratory system which carry air directly to the cells in the tissues?
Answer:
Trachioles, the fine branches of trachea carry air directly to the cells in the tissues.

Question 40.
What are the respiratory organs in fishes?
Answer:
Gills or bronchiae are the respiratory organs in fishes.

Question 41.
What is cutaneous respiration?
Answer:
If the respiration occurs through skin, it is known as cutaneous respiration, e.g : Leech, Earthworm and Frog.

Question 42.
What are the other areas on the plant body through which gaseous exchange take place?
Answer:
The areas on the plant body through which geseous exchange take place are the surface of roots, lenticels on the stem.

Question 43.
What is the full form of ATP? How is it formed?
Answer:
I) ATP stands for Adenosine triphosphate.
2) ATP is used to supply energy in the cells for the carrying all the metabolic processes.

Question 44.
What are the factors that control respiration?
Answer:
Oxygen and temperature are the two important factors that control the process of respiration.

Question 45.
What are the substances that are used for the production of energy in all living organisms?
Answer:
Glucose and fatty acids are used for the production of energy in all living organisms.

Question 46.
How many types of respiration are present? What are they?
Answer:
There are two types of respiration. They are :

1. Aerobic respiration and
2. Anaerobic respiration.

Question 47.
Where is energy stored in ATP?
Answer:
Energy is stored in the terminal phosphate bond in ATP which is having three phosphates attached to a molecule of Adenosine.

Question 48.
What are the power houses of the cell?
Answer:
Mitochondria are the power houses of the cell.

Question 49.
What is the main difference between respiration and combustion?
Answer:
In respiration several intermediates are produced and in combustion, there are no such intermediates are produced.

Question 50.
What is the equation that represents respiration?
Answer:
The equation that represents respiration is

Question 51.

.
What are the sites of cellular respiration?
Answer:
Mitochondria are the sites of cellular respiration.

Question 52.
What are cristae in mitochondria?
Answer:
The inner membrane of mitochondria is thrown into several folds called cristae.

Question 53.
What is the net gain of ATP molecules in Glycolysis?
Answer:

1. Four ATP molecules are produced when one molecule of glucose is converted to two molecules of pyruvate but two are consumed.
2. The remaining two ATP molecules are net gain in glycolysis.

Question 54.
How many ATP molecules are produced when one glucose molecule is completely oxidised?
Answer:
A net gain of 38 ATP molecules are formed from the total oxidation of one glucose molecule.

Question 55.
What are the three stages present in complete oxidation of glucose molecule?
Answer:
The three stages present in complete oxidation of glucose molecule are

1. Glycolysis
2. Kreb’s cycle and
3. Electron transport.

Question 56.
Why does oxidation of fatty acids give more energy?
Answer:
Oxidation of fatty acids give more energy due to the presence of more carbon atoms in them.

Question 57.
What are aquatic and terrestrial animals?
Answer:
Animals that live in water are called aquatic animals and that live on land are known as terrestrial animals.

Question 58.
Why is the rate of breathing in aquatic organisms much faster than terrestrial organisms?
Answer:

1. The amount of oxygen dissolved in water is low when compared to the amount of oxygen present in air.
2. Therefore the rate of breathing in aquatic animals is much faster than in terrestrial animals.

Question 59.
Which part of the roots is involved in the exchange of respiratory gases?
Answer:
The part of roots that are involved in the exchange of respiratory gases are root hairs.

Question 60.
What is the average breathing rate in an adult mem at rest?
Answer:
The average breathing rate in an adult man at rest is about 15 to 18 times per minute.

Question 61.
Why is the trachea prevented from collapsing?
Answer:
The walls of the trachea are supported by several ‘C’ shaped cartillagenous rings. They prevent the trachea from collapsing and closing.

Question 62.
Why deos the percentage of carbon dioxide increase in exhaled air?
Answer:
During oxidation of glucose carbon dioxide is produced as waste product. Hence the concentration of carbon dioxide increases in exhaled air.

Question 63.
How does breathing take place in mangrove plants?
Answer:
In mangrove plants breathing takes place through specialised structures called breath¬ing roots or pneumatophores.

Question 64.
How does respiration take place in plants where roots are present in wet places?
Answer:
The plants which have their roots in very wet places have much larger air spaces, connect the stems with the roots, making diffusion from upper parts.

Question 65.
Which form a continuous network all over the plant?
Answer:
The stomatal openings lead to a series of spaces between the cells inside the plant which form a continuous network all over the plant.

Question 66.
What are the reasons for the animals to develop different types of respiratory organs?
Answer:
Body size, availability of water, habitat in which they live and the type of circulatory system are some of the reasons for the animals to develop different types of respiratory organs.

Question 67.
Why do fishes die when taken out of water?
Answer:
Fishes do not have lungs to utilise oxygen for breathing. They have gills which can utilize only dissolved oxygen from water.

Question 68.
What would be the consequences of deficiency of haemoglobin in our bodies?
Answer:
Deficiency of haemoglobin in blood can affect the oxygen supplying capacity of blood to body cells. It can also lead to a disease called Anaemia.

Question 69.
What are the stages of respiration in man?
Answer:
Respiration in man occurs in two stages 1) Inhalation (or) Inspiration 2) Exhalation (or) Expiration.

Question 70.
Which part plays major role in respiration of man?
Answer:
Diaphragm plays a major role in respiration in man.

Question 71.
Which part plays major role in respiration of woman?
Answer:
In woman ribs play a major role in respiration.

Question 72.
How are lungs protected?
Answer:
Lungs are protected by two membranes called pleura. A fluid between these membranes protects the lungs from injury.

Question 73.
What is the composition of exhaled air?
Answer:
Exhaled air contains 16% of oxygen, 4% of carbon dioxide and 79% of nitrogen.

Question 74.
Why are red blood cells red in colour?
Answer:
Red blood cells are red in colour due to the presence of haemoglobin in their cytoplasm.

Question 75.
How is haemoglobin made up of?
Answer:
Haemoglobin is made up of a protein called globin, Iron (Hearn) and organic molecule called porphyrin.

10th Class Biology 2nd Lesson Respiration 2 Marks Important Questions and Answers

Question 1.
(a) Which gas turns lime water milky in this experiment?
Answer:
Carbondioxide (or) CO₂

(b) Which gas do you think might be present in less quantities in the air we breath out as compared to air around us?
Answer:
Oxygen (or) O₂

Question 2.
Balu said that, “Plants perform Photosynthesis during day time. They respire during night time”.
Do you agree with Bain? Why? Why not?
Answer:

1. I do not agree with Balu’s statement.
2. Photosynthesis depends on light for energy but respiration does not depend on light.
3. Hence, photosynthesis takes place during day time only whereas respiration takes place both day and night.

Question 3.
The sportsman who participated in 100 mtr race get more muscle pains. But the sportsman who participates in 5 km’s race get less muscle pains. What is the reason?
Answer:

1. Accumulation of lactic acid results in muscular pain.
2. During 100 m race a well trained athlete can hold his breath and afterwards he pants.
3. In this case, the muscles are using energy released during the anaerobic break down of glucose, lactic acid is produced.
4. The presence of lactic acid in the blood is the main cause of muscle fatigue. Whether it is 100 mtr race or 5 km race.
5. If the body is rested long enough the tiredness goes.

Question 4.
What happens if there is no epiglottis in human beings?
Answer:

1. Food may enters into the larynx.
2. Food may enters into the lungs leading to the death.
3. May not speak properly.
4. Entry of food and air may not be regulated properly.

Question 5.
Write two chemicals and two materials required to conduct the experiment “Heat and Carbon dioxide are evolved during anaerobic respiration”.
Materials required: Thermosflask, splitted corks, thermometer, wash bottle, glass tubes.
Chemicals required: Liquid paraffin, glucose solution, bicarbonate solution, Janus green B and Yeast cells.

Question 6.
Observe the below diagram.
A) To which biosystem is this picture related?
Answer:
Respiratory system.

B) Write the names of the parts of A, B.
Answer:
A – alveolus; B – blood capillary network

C) To which system are they linked with?
Answer:
Respiratory system; circulatory system.

D) Which process is happening here? What happens as a result of it?
Answer:
Gaseous exchange between alveolus of lungs and blood capillaries. Due to this the CO₂, present in blood capillaries enter alveolus and oxygen present in alveolus en¬ter blood capillaries.

Question 7.
A person reached a specific distance once on foot and once by running. In which situation his legs pain? Why?
Answer:

1. When a person runs to reach a specific distance gets pain in his legs.
2. This is due to the production of lactic acid in the muscles.
3. Due to the Anaerobic respiration glucose in muscles converts into lactic Acid.
4. Accumulation of lactic acid causes pain in leg muscles.

Question 8.
What is the advantage of the wet and warm passage of air from the nostrils to capillaries?
Answer:
When the air passes in nasal cavity and in the pharynx some changes take place.

1. The mucus layer and hair in the nasal cavity removes the dust particles in the air.
2. The temperature of the air brought to the body temperature.
3. Moistening the air.

Question 9.
In the experiment of anaerobic respiration with yeast
i) Why was liquid paraffin poured on glucose?
ii) What did you understood about anaerobic respiration?
Answer:
i) The supply of oxygen from the air can be stopped by pouring liquid paraffin on glucose.
ii) Anaerobic respiration takes place in the absence of oxygen. In this glucose molecule is incompletely oxidised. The end products of anaerobic respiration are ethyl alcohol or lactic acid and CO₂.
During anaerobic respiration small amount of energy is liberated (2ATP). Anaero¬bic respiration occurs in many anaerobic bacteria and human muscles cells. The anaero¬bic respiration can be represented as:
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂+ 56 K.Cal.

Question 10.
See the below table. Write what you know from it.

Gas	% in inhaled air	% of exhaled air
Oxygen	21	16
Carbon dioxide	0.04	4
Nitrogen	79	79

Answer:

1. The inhaled air consists of 21% of oxygen whereas the exhaled air contains 16% of oxygen only. This is due to utlilisation of oxygen during cellular respiration in the body. Hence the difference occurs.
2. Inhaled air contains 0.04% of carbondioxide whereas exhale air contains 4% of carbondioxide.
   The concentration of CO₂ is increased a lot due to the release of CO₂ during cellular respiration in the body.
3. Both inhale and exhale air contains 79% of nitrogen because nitrogen has no role to play in cellular respiration.

Question 11.
What is the pathway of air from nostril to alveolus?
Answer:
Draw a flow chart of Respiratory passage of Humans.

Question 12.
What happens when a baker prepares a dough by mixing yeast in it?
Answer:

1. The yeast is commonly used for fermenting bread is saccharomyces cerevisiae.
2. Baker’s yeast has the advantage of producing uniform, quick, and reliable results because it is obtained from pure culture.
3. Water is mixed with flour, salt and the fermenting agent.
4. The mixed dough is then allowed to rise one or more times.
5. Then loaves are formed and the bread is baked in air oven.

Question 13.
How does respiration in amoeba and hydra occur through diffusion? (OR)
What are the similarities in respiration of amoeba and hydra?
Answer:

1. Amoeba and hydra are aquatic organisms.
2. Respiration in them occurs through diffusion.
3. As oxygen is used by these organisms in respiration, its concentration is reduced in cytoplasm. Hence oxygen diffuses into cytoplasm from surrounding water.
4. During respiration CO₂ is continuously produced, its concentration increases in the cytoplasm, hence it diffuses into surrounding water.

Question 14.
Write a short note on ATP. (OR) Expand ATP.
Answer:

1. From the break down of glucose the energy is released and stored up in a special compound known as ATP (Adenosine Triphosphate).
2. It is a small parcel of chemical energy. The energy currency of these cells is ATP an energy rich compound that is capable of supplying energy whenever needed within the cell.
3. Each ATP molecule gives 7200 calories of energy. This energy is stored in the form of phosphate bonds.
4. If the bond is broken, the stored energy is released.

Question 15.
How do Dolphin and Crocodile respire?
Answer:

1. The aquatic animals like dolphin and crocodile respire with the help of lungs.
2. They come out of the water for air.
3. These two animals were lived on land initially.
4. Later they lived in water and developed several adaptations to live in water.

Question 16.
Why are Mitochondria called “Power houses of cell”? (QR)
What is the energy producing organ in a cell? How does it produce energy?
Answer:

1. Cellular respiration in prokaryotic cells like that of bacteria occurs within the cytoplasm.
2. In eukaryotic cells cytoplasm and mitochondria are the sites of reaction.
3. The produced energy is stored in mitochandria in the form of ATP.
4. Hence, mitochondria are called “Power houses of cell”.

Question 17.
Write the rate of respiration in different age groups of human beings.
Answer:

1. Newborn child: 32 times per minute
2. Children of 5 years: 26 times per minute
3. Man of 25 years: 15 times per minute
4. Man of 50 years: 18 times per minute

10th Class Biology 2nd Lesson Respiration 4 Marks Important Questions and Answers

Question 1.
Write about respiration in mangroves that grow in marshy lands.
Answer:

1. Mangroves grown near the marshy places respire through aerial roots or respiratory roots.
2. The root hairs exchange the gases from their surface.
3. They obtain oxygen from the airspaces present between the soil particles.
4. The plants grown in marshy places are adapted to develop aerial roots above the soil surface which helps in gaseous exchange.

Question 2.
a) What is the aim of this experiment?
Answer:
Heat is liberated during respiration.

b) What change do you observe in thermometer readings?
Answer:
Reading increases in the thermometer.

c) In your opinion, where did this heat come from?
Answer:
The heat comes from the germinating seeds which respire and releasing heat.

d) What precaution should we take, while doing this experiment?
Answer:
The bulb of the thermometer should be dip in the germinating seeds (or) sprouts.

Question 3.
You have conducted this experiment in your classroom. Now answer the following questions.
a) What do you prove by conducting this experiment?
Answer:
To test the production of heat and carbon dioxide during anaerobic respiration.

b) Why do you heat glucose solution?
Answer:
To remove the dissolved oxygen in the glucose solution.

c) How do you confirm that glucose solution is free from oxygen after heating it?
Answer:
By adding diazine green (Janus green B) solution to glucose solution, it turns to pink.

d) What are the changes you notice in the lime water?
Answer:
Lime water turns milky white.

Question 4.

i) What change did you observe in the thermometer in the given experiment?
Answer:
Raise in the temperature

ii) Where does the heat come from?
Answer:
From the germinating seeds during respiration

iii) What result you will get, if you perform this experiment with dry seeds?
Answer:
No change of temperature in thermometre.

iv) What are the apparatus used in this experiment?
Answer:
Glass jar, germinating seeds, cork, thermometer.

Question 5.
Observe the set of apparatus and answer the following questions.
i) Which process do we know with the help of this experiment?
Answer:
Combustion.

ii) How does this process differ with respiration?
Answer:
Respiration occurs in the presence of water.
Combustion occurs in the absence of water.

iii) What are the similarities between this process and respiration?
Answer:
In both processes energy is released.

iv) Which gas turns lime – water milky?
Answer:
Carbon-di-oxide (CO₂)

Question 6.
Look at the following experiment. Answer the questions.

a) What is the aim of the experiment?
Answer:
The aim of the experiment is CO₂ is released during anaerobic respiration.

b) Which agent is used to find the presence of oxygen?
What changes do you observe when oxygen is present in Glucose solution?
Answer:
To find the presence of oxygen diazine green (Janus Green B) solution is used. The blue diazine green solution turns pink when oxygen is present in the glucose solution.

c) Why is liquid paraffin poured on glucose solution?
Answer:
By pouring liquid paraffin on glucose solution, the supply of oxygen from the air can be cut off.

d) Which gas is released during the experiment? How can you prove it?
Answer:
Carbon dioxide is released.
The released CO₂ passes into lime water it turns milky.

Question 7.
Observe the following diagram and answer the following questions.

1. What do we call the membranes that cover the lungs?
2. What is the functional unit of lungs ?
3. Which part produces the sound ?
4. What does ‘X’ denote ?

Answer:

1. Pleura
2. Alveoli
3. Larynx
4. Trachea

Question 8.
Observe the diagram and answer the following questions.

a) What does the given diagram indicate?
b) What is the part ‘X’ in the diagram?
c) What is the function of the given picture?
d) To which system the given picture belongs to?
Answer:
a) The given diagram indicates mitochondria.
b) Matrix
c) Performing cellular respiration and releasing energy in the form of ATP.
d) Respiratory system.

Question 9.
Observe the experimental setup and answer the given questions.
A) What is the aim of this experiment?
B) What are the apparatus required for this experiment?
C) What changes do you observe in thermometer during this WKm experiment?
D) What will happen, if dry seeds are taken instead of germinating seeds in this experiment?
Answer:
A) Heat is liberated during respiration.
B) Glass jar, Germinating seeds, Cork and Thermometer.
C) We can notice the raise in temperature after observing the thermometer readings.
D) There will be no change of temperature in the thermometer. We can’t prove the aim of the experiment.

Question 10.
Observe the below diagram and answer the following questions:
i) What does the above setting (diagram) indicate?
Answer:
The above setting (diagram) indicates to prove that carbon dioxide and heat are liberated during anaerobic respiration by yeast cells.

ii) Why is boiled and cooled glucose covered with paraffin?
Answer:
To prevent supply of air, boiled and cooled glucose is covered with paraffin.

iii) What is the use of adding diazine green to glucose solution? What change you notice in glucose solution?
Answer:
Diazine green is added to glucose solution to know whether oxygen is present or not in glucose solution. When the availability of oxygen is less the diazine green changes to pink colour.

iv) Why is lime water used in this experiment?
Answer:
To know whether carbon dioxide is released or not in this experiment lime water is used. Carbon dioxide changes lime water to milky white.

v) Why is bulb of thermometer dipped in the glucose water?
Answer:
To know the rise in temperature of glucose solution when heated, the bulb of thermometer is dipped in the glucose water.

Question 11.
Explain with the help of a flow chart, the path way of air in humans.
Answer:

Question 12.
Study the graph and answer the following questions :
Graph showing effects of vigorous excercise on the concentration of lactic acid in blood.
i) What was the concentration of lactic acid in blood to start with?
ii) What was the greatest concentration of lactic acid reached during the experiment?
iii) What is the concentration of lactic acid after 25 minutes of exercise?
iv) What is the relationship between lactic acid and muscle pain?
Answer:
i) 20 mg/cm³
ii) 20 minutes (Or) at “B” point,
iii) 101 mg/cm³
iv) If concentration of lactic acid increases, muscle pains also increases.

Question 13.
Observe the following :

Write the answers to the following questions:
i) How many Pyruvic acid molecules form from one Glucose?
Answer:
2 Pyruvic acid molecules.

ii) What conditions influence Pyruvic acid to participate in Aerobic and Anaerobic respiration?
Answer:
Presence of oxygen

iii) In which we get more energy in both Aerobic and Anaerobic respirations?
Answer:
Aerobic respiration

iv) The chemical that is formed in human muscles during Anaerobic respiration.
Answer:
Lactic acid

Question 14.
Why does the exchange of gases happen only in alveoli, though arteries are present in pharynx, trachea and bronchus?
Answer:

1. Alveoli are tiny air sacs in the lungs surrounded by capillaries
2. They are numerous and only single cell thickness
3. They increase the efficiency of gas exchange.
4. Due to the difference in a gradient of O₂ oxygen diffuse from alveoli to blood capillaries.

Question 15.
What are the events or steps in respiration?
Answer:
The following are the events or steps in respiration.

1. Breathing: Air moves into lungs and out of lungs.
2. Gaseous exchange in lungs: Exchange of gases between alveoli and blood.
3. Gas transport by blood: Transport of oxygen from blood capillaries of alveoli to body cells and return of carbon dioxide.
4. Gaseous exchange in cells: Exchanging oxygen from blood into the cells and carbon dioxide from cells into the blood.
5. Cellular respiration: Using oxygen in cell processes to produce carbon dioxide and water, releasing energy to be used for life processes.

Question 16.
What will happen if the respiratory tract is not moist? (OR)
Why respiratory tract should be moist?
Answer:

1. If the respiratory tract is not moist the dirt particles in the inhaled air will not be removed from air in the nasal cavities and reaches lungs and creates problems to lungs.
2. The temperature of the inhaled air is brought close to that of the body for the smooth passage in the respiratory tract. If it is dry, it is not possible.
3. If the surface dries out, gas exchange will happen at a very reduced rate since fast moving gaseous oxygen molecules do not efficiently cross the alveoli membrane.
4. The reduced gas exchange is most likely not enough to support blood oxygenation for vital functions.
5. Hence respiratory tract should be moist for smooth exchange of gases.

Question 17.
Explain the process of transportation of gases through the blood.
Answer:

1. The relative amount of gases and their combining capacity with haemoglobin and other substances in blood determine their transport via blood in the body.
2. When oxygen present in the air is within normal limits (around 21%) then almost all of it is carried in the blood by binding to haemoglobin, a protein present in the red blood cells.
3. As oxygen is diffused in the blood, it rapidly combines with the haemoglobin to form oxyhaemoglobin.
4. Not only can haemoglobin combine with oxygen, but it can easily broken into haemoglobin and oxygen.
5. Carbon dioxide is usually transported as bicarbonate, while some amount of it combines with haemoglobin and rest is dissolved in blood plasma.
   

Question 18.
Why is human life impossible at higher altitudes without a supplementary supply of oxygen? (OR)
The concentration of oxygen in air decreases as we go up from sea level. Explain briefly.
Answer:

1. If haemoglobin is exposed to air at sea level, every molecule in air combines with oxygen to form oxyhaemoglobin.
2. At a height of 13 km above sea level, the concentration of oxygen is much lower about l/5th of a sea level.
3. Under these conditions about half as many molecules of oxygen combine with haemoglobin to form oxyhaemoglobin.
4. Blood cannot carry enough oxygen to the tissues.
5. Hence human life is impossible at such a high altitude without a supplementary supply of oxygen.
6. Provision for such a supply is built into modern aircraft which have pressurized cabins that maintain an enriched air supply.

Question 19.
What are the different ways in which glucose is oxidised to provide energy in various organisms? Give one example of each.
How does oxidation of glucose occur in various organisms?
Answer:

1. Glucose is the most commonly used sugar for deriving energy in plants, animals and in microorganisms.
2. In all these organisms glucose is oxidized in two stages.
3. The first stage is known as Glycolysis. It occurs in cytoplasm.
4. During glycolysis glucose is converted to two molecules of pyruvic acid.
5. In the second stage if oxygen is available pyruvic acid is converted to C02 and water, large amount of energy is released. This is known as aerobic respiration. It occurs in most of the plant and animal cells.
6. If oxygen is inadequate or not available, pyruvic acid is converted into ethanol and carbon dioxide. This is anaerobic respiration taking place in yeast cells that is called fermentation.
7. If oxygen is not available in muscle cells, the pyruvic acid is converted into lactic acid.
   

Question 20.
Write the adaptations seen in plants living in water logged conditions.
(OR)
What are the adaptations seen in magrove plants?
Answer:

1. Most plants can aerate their roots by taking in the oxygen through lenticels or through the surface of their root hairs.
2. But plants which have their roots in very wet places, are unable to do this.
3. They are adapted to these water logged conditions by having much larger air spaces which connect the stems with the roots, making diffusion from the upper parts much more efficiently.
4. The problem of air transportion is more difficult for trees and may not survive with their roots permanently in water.
5. To overcome this problem the mangrove tree of the tropics which raise up aerial roots above the surface and takes in oxygen.

Question 21.
Describe the mechanism of branchial or gill respiration in fishes.
(OR)
Briefly explain the process of exchange of gases in fishes during respiration.
Answer:

1. Some aquatic animals like fishes have developed special organs for respiration which are known as gills or branchiae.
2. Blood is supplied to gills through capillaries which have thin walls where gases are exchanged. Gills are present in the gill pouches or branchial pouches.
   
3. Gills are provided with leaf-like folds called gill lamellae.
4. Fish keeps its mouth open and lowers the floor of the oral cavity. As a result water from outside will be drawn into the oral cavity.
5. Now the mouth is closed and the floor of the oral cavity is raised.
6. Water is pushed into the pharynx and is forced to gill pouches through internal branchia apertures.
7. When water passes through gill lamellae exchange of gases takes place, that is oxygen diffuses from water to blood and CO₂ from blood into water.
8. Then water flows through external branchia aperture.

Question 22.
Explain briefly about Pranayama- the art of breathing. (OR)
How can the capacity of lungs be improved by yoga?
Answer:

1. To improve breathing capacity the saint Patanjali developed Yogabyasa.
2. The art of breathing in Yogabyasa is called Pranayama. Prana means gas, ayama means journey.
3. In Pranayama practice air is allowed to enter three lobes of lungs in order to in¬crease the amount of oxygen to diffuse into blood.
4. More amount of oxygen available to brain and tissues the body will be more active.
5. It is very important to practise Pranayama regularly to make our life healthy and active.
6. All people irrespective of age and sex should practise Pranayama under the guidance of well trained Yoga Teacher to improve the working capacity of lungs.

Question 23.
What are the experiments carried out by Lavoisier to understand the property of gases?
Answer:

1. In his early experiments Lavoisier thought that the gas liberated on heating powdered charcoal in a bell jar kept over water in a trough was like fixed air i.e., carbon dioxide.
2. The next series of experiments deals with the combustion of phosphorous in a bell jar. From this he showed that whatever it was in the atmospheric air which combined with the phosphorous was not water vapour.
3. This was respirable air, a component of air that also helped in burning.
4. The air that we breathe out precipitated lime water while that after heating metal did not.
5. From this, he concluded that there were two processes involved in respiration.
6. Lavoisier carried out another experiment by which he showed that about one sixth of the volume of ‘vitiated air’ consists of chalky acid gas (fixed air).
7. Either eminently respirable air is changed in the lungs to chalky acid air; or an exchange takes place, the eminently respirable air being absorbed, and an almost equal volume of chalky acid air being given up to the air from the lungs.
8. Lavoisier had to admit that there were strong grounds for believing that eminently respirable air did combine with the blood to produce the red colour.

Question 24.
Explain the evolutionary changes in energy-releasing system.
(OR)
What are the different respiratory systems in animal groups?
Answer:
Exchange of gases is a common life process in all living organisms, but it is not same in all.

1. Diffusion:
   1. Single-celled organisms like amoeba or multicellular organisms like hydra and planarians obtain oxygen and expel carbon dioxide directly from the body by the process of diffusion.
   2. In multicellular animals special organs are evolved.
   3. Body size, availability of water and the type of circulatory system are some of the reasons for the animals to develop different types of respiratory organs.
2. Tracheal respiratory system : In insects tracheal respiratory system is present in which small branches of trachea called trachioles carry air directly to the cells in the tissues.
3. Bronchial respiration : In fishes gills are utilised for the exchanges of gases. Blood is supplied to gills through capillaries which have thin walls for exchange of gases. This is called bronchial respiration.
4. Cutaneous respiration: 0 Respiration through skin is called cutaneous respiration.
   Eg: i) Earth worms and leeches.
   ii) Frog, an amphibian can respire through lungs and skin.
5. Pulmonary respiration : Most of the higher animals respire with the help of lungs. This type of respiration is known as pulmonary respiration. Eg: Mammals.

Question 25.
Describe the structure of mitochondria with the help of a diagram. (OR)
Which cell organelle is called energy currency or power house of cell? What do you know about its construction?
Answer:
Mitochondria is known as energy currency or power house of cell.
Structure of mitochondria:

1. Mitochondria are sac-like structures present in the cytoplasm of the cells.
2. Mitochondria have two compartments-an inner compartment and an outer compartment. The substance in the inner compartment is called matrix.
3. The matrix is surrounded by a membrane called inner membrane of mitochondria.
4. The inner membrane is thrown into several folds called cristae. The cristae extended into the matrix.
5. The space between the folds is continuous with the outer compartment.
6. On the inner membrane, projecting into the matrix are a large number of particles called elementary particles.
7. These particles have a spherical head and a stalk. They are attached to the inner membrane by their stalk and the head portion of the particle is in the matrix.
8. The outer compartment is surrounded by another membrane – the outer membrane. The outer membrane is smooth and has no projections.
9. The inner membrane, the matrix and the elementary particles in the mitochondria have large number of enzymes and other required proteins for the respiration and energy production.

Question 26.
Draw and label mitochondria. Why should we call it cell of power ?
Answer:

Oxidation of glucose molecule occurs in the mitochondria, ot cell. This is known as cellular respiration. The energy produced during cellular respiration stored in the form of ATP molecule. Energy producing cellular respiration occurs in mitochondria hence we call it cell of power or power house of the ceil.

Question 27.
Describe how oxygen enters the blood in lungs with the help of block diagram.
(OR)
How does gaseous exchange occur in lungs?
Answer:

1. Gaseous exchange takes place within the lungs by diffusion from the alveoli to blood capillaries and vice versa. Alveoli in lungs are numerous and only one cell thick.
   
2. Alveoli are surrounded by capillaries that are also one cell thick.
3. Blood, dark red in colour flows from the heart through these capillaries and collects oxygen from the alveoli.
   At the same time, carbon dioxide passes out of the capillaries and into the alveoli.
4. When we breathe out, we get rid of carbon dioxide.
5. The bright red, oxygen rich blood is returned to the heart and pumped out to all parts of the body.

Question 28.
What is the role of diaphragm and ribs in respiration? Are both active in man and woman?
Answer:
Diaphragm:

1. Diaphragm is a muscular dome shaped tissue present at the floor of the chest cavity separating abdomen from respiratory system.
2. Diaphragm expands downwards into the abdomen thus increasing chest cavity. This allows the lungs to expand as we inhale.
3. As the diaphragm contracts upwards thus decreasing the chest cavity, it allows the air to expel from the lungs.
   Ribs:
4. The ribs protect the lungs and expand as we inhale to facilitate space for the lungs to expand. The ribs then contract expelling the air from the lungs.
5. The intercostal muscles present between the ribs help in contraction and relaxation of ribs.
6. In man, diaphragm plays a major role in the respiration, while in woman, the ribs play a major role.

Question 29.
Why are alveoli so small and uncountable in number? (OR)
How do alveoli increase the area for exchange of gases?
Answer:

1. The pouch-like air sacs at the ends of the smallest branchioles are called alveoli.
2. The walls of the alveolus are very thin and they are surrounded by very thin blood capillaries.
3. It is in the alveoli that gaseous exchange takes place.
4. There are millions of alveoli in the lungs. The presence of millions of alveoli in the lungs provides a very large area for the exchange of gases.
5. And the availability of large surface area maximises the exchanges of gases.

Question 30.
Write a brief note on respiration in plants. (OR)
Does respiration occur in plants? Explain briefly about it.
Answer:

1. In most plants exchange of gases takes place through stomata.
2. There are other areas on the plant body like surface of roots, lenticels on stem, etc. the gaseous exchange takes place.
   
3. Some plants have specialized structures like breathing roots of mangrove plants as well as the tissue in orchids.
4. Breathing roots and tissue in orchids help plants to take oxygen to produce energy and release carbon dioxide.
5. Inside the plants openings lead to a series of spaces between the cells which form a continuous network all over the plant.
6. The whole system works by diffusion.
7. As the oxygen is used up by the cells a gradient develops between the cells and the air in the spaces.
8. So oxygen passes in between the air spaces and the air outside stomata and lenticels.
9. In the same way, as more carbon dioxide is given out by the cells, a gradient occurs in the reverse direction and it passes out.

Question 31.
Write a brief note on tracheal respiration in insects.
Answer:

1. In insects blood do not contain haemoglobin, and blood is white in colour. Hence it cannot carry oxygen.
2. For respiration insects adopt a special system called tracheal system.
   
3. This system consists of a series of tubes called trachea.
4. These trachea open out through small apertures called spiracles on either side of the body.
5. All tracheal tubes of each side join and form a longitudinal tracheal trunk.
6. Trachea divide into a number of branches called tracheoles which carry air directly to the tissues.
7. As the air moves in and out of the trachea, oxygen present in the air diffuses into the cells and CO₂ diffuses into the air from the cells.

Question 32.
Write about the mechanism of respiration in human beings. (OR)
How does exchange of gases take place in human beings?
Answer:

1. Respiration in man occurs in two stages. They are inspiration and expiration.
2. During inspiration air from outside enters into the lungs by increasing the chest cavity.
   
3. Increase in the chest cavity is made by pulling the diaphragm down and pushing the ribs forward.
4. As the air pressure in the lungs is reduced, air from outside enters the lungs through external nostrils, nasal cavities, internal nares, pharynx, epiglottis, larynx, trachea, bronchi and branchioles and finally reach the alveoli where exchange of gases takes place.
5. During expiration the diaphragm and ribs come back to original positions.
   
6. This reduces the volume of chest cavity.
7. So the volume of lungs is decreased and air under pressure comes out of the lungs.

Question 33.
Study the graph given below and analyse the reasons for accumulation of lactic acid in blood after strenuous exercise.

Answer:

1. This graph shows the relation between time accumulation of lactic acid in the muscles.
2. At the beginning, the amount of lactic acid in the blood is very less.
3. Gradually it is increased by vigorous exercise.
4. Within 15 minutes it goes to maximum level which causes muscle pain.
5. Then the lactic acid is removed from muscles in an hour.
6. Muscles produce energy by anaerobic respiration.
   C₆H₁₂O₆ → lactic acid + CO₂ + energy
7. In the vigorous exercise, muscle work rapidly and produce more lactic acid.
8. That’s why lactic acid concentration is increased in muscle after strenuous exercise.

Question 34.
Observe the above graph of lactic acid accumulation in the muscles of an athlete and answer the following questions.
a) What was the concentration of lactic acid in the blood to start with?
Answer:
It is 20 mg/km³.

b) What was the greatest concentration reached during the experiment?
Answer:
101 mg/cm³.

c) If the trend between points C and D were to continue at the same rate, how long might it take for the original lactic acid level to be reached once again?
Answer:
55 minutes.

d) What does high level of lactic acid indicate about the condition of respiration?
Answer:
It indicates the accumulation of lactic acid in muscles through anaerobic respiration. The presence of lactic acid in the blood is the main cause of muscular pain and fatigue.

Question 35.
Describe the structure of human lungs with the help of a diagram.

Answer:

1. A pair of lungs is present in the chest cavity one on either side of the heart.
2. Lungs are spongy and elastic. They are enclosed by two membranes called pleura.
3. Space between the two membranes of pleura is filled with fluid. Pleura protects the lungs from injury.
4. Right lung is larger than the left lung.
5. Right lung is made of three lobes while the left lung has only two lobes.
6. Lung has several thousands of alveoli which are supplied with blood capillaries.
7. Pulmonary artery brings deoxygenated blood from heart to lungs.
8. After entering the lung, this artery divides into several arterioles and capillaries and supplies deoxygenated blood to alveoli.
9. Gas exchange occurs in the alveoli.
10. Oxygenated blood is carried from the lung to heart by the pulmonary vein.

Project work
Question 1.
Observe and analyse the questions in the table given below.

	Newly borned	(Children)	(Children)	Children	Youth/Adults	Athletics
	(0-3 months)	(3-6 months)	(6-12 months)	(1-10 years)
Heart beat	100 -150	90-120	80 -120	70-130	60-100	40-60

A) In which age group rate of heart beat is more?
B) In which age group rate of heart beat is less?
C) Why heart beat in Athletics is less?
D) What are reasons for more rate of heart beats differences between the newly born and children?
Answer:
A) In newly borned babies which are in 0 – 3 months of age group rate of heart beat is more i.e., 100 to 150 times.
B) In athletics the rate of heart beat is less i.e., 40 – 60 times / minute.
C) The heart of athlete pump more blood per beat due to increased cardio-vascular fitness in the structure of the heart. The muscles in the heart wall thicken and the heart pumps more blood with each beat.
D)

1. Mothers who have special medical conditions such as thyroid diseases or diabetes may give birth to new borns who are temporarily tachscardic from altered hormone and glucose levels. Tachycardia is a medical term for a very rapid heart beat.
2. Some infants are born with accessory electrical tissue in the heart causes epi¬sodes of rapid heart rate.
3. In wolf – parkinson syndrome – white syndrome there are extra cells and an ac-cessory path way, causing additional heart beats.

Question 2.
Observe the table given below and analyse the questions.

Name of the animal	Weight of the body	Weight of the heart	No. of beats/min
Blue whale	1,30,000 kg	750 kg	7
Elephant	3000 kg	12-21 kg	46
Man	60 – 70 kg	300 gm	76
Coaltit (Bird)	8 gm	0.15 gm	1200

A) Why heart beat is less in animals with more weight?
B) Why heart beat is more in animals with less weight?
C) What is the relationship between weight of the body and rate of heart beat?
D) Why the weight of heart is less than body weight?
Answer:
A) The animals with more weight usually have weighted hearts. In one heart beat the large-sized hearts sends high amounts of blood to circulatory system. It takes time for the fulfilment of heart. Hence heart beat is less in animals with more body weight.
B) Usually the heart is very small in less weight animals. When the animal shrinks or contracts , its heart actually decrease the volume of blood proportionately. It can compensate for the reduced volume by increasing the rate at which it can supply blood to all body parts.
C) As the weight of the body of the animal increases the rate of heart beat per minute decreases. And also as the weight of the body decrease the rate of heart beat increases.
D) Usually the body of an organism is made by number of organs which makes the body functional. As all the body parts constitute the whole organism, the heart one of the organ is usually has less weight than body weight of an animal.

AP State Board Syllabus AP SSC 10th Class Physics Solutions Chapter 5 Refraction of Light at Plane Surfaces Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Physics Solutions 5th Lesson Refraction of Light at Plane Surfaces

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Textbook Questions and Answers

Improve Your Learning

Question 1.
Why is it difficult to shoot a fish swimming in water? (AS1)
(OR)
If the fish is swimming in water, why it is difficult to shoot?
(OR)
A shooter finds it difficult to shoot a fish swimming in water. Why?
Answer:
Due to refraction of light, it is difficult to shoot a fish swimming in water.

Reason :
The light rays coming from the fish towards shooter, bend at water-air interface. So, shooter sees only image of the fish, but not actual fish.

Question 2.
The speed of light in a diamond is 1,24,000 km/s. Find the refractive index of diamond if the speed of light in air is 3,00,000 km/s. (AS1)
Answer:
Speed of light in diamond = 1,24,000 km/s
Speed of light in vacuum = 3,00,000 km/s

Question 3.
Refractive index of glass relative to water is 9/8. What is the refractive index of water relative to glass? (AS1)
Answer:
Refractive index of glass relative to water = \(\frac{n_{g}}{n_{w}}=\frac{9}{8}\)
∴ Refractive index of water relative to glass = \(\frac{\mathrm{n}_{\mathrm{w}}}{\mathrm{n}_{\mathrm{g}}}=\frac{8}{9} \cdot\left[\because \mathrm{n}_{12}=\frac{1}{\mathrm{n}_{21}}\right]\)

Question 4.
The absolute refractive index of water is 4/3. What is the critical angle ? (AS1)
Answer:
Absolute refractive index of water = 4/3

Critical angle of water = C = 48°5′ = 48.5°.

Question 5.
Determine the refractive index of benzene if the critical angle is 42°. (AS1)
Answer:
Critical angle of benzene = 42°.

Question 6.
Explain the formation of mirage. (AS1)
(OR)
How is the mirage formed? Explain.
(OR)
A person walking on a road observed some water being present on the road but when he went there actually he did not find water. What is that actually formed called? Explain that process.
(OR)
Sometimes during the hot summer at noon time on tar roads, it appears that there is water on the road, but there would really be no water. What do you call this phenomenon? Explain why it happens.
(OR)
Why do you see a mirage the road on a hot summer day?
Answer:

• During hot summer day, air just above the road surface is very hot and the air at higher altitudes is cool.
• We know that refractive index of air increases with density.
• So, the cooler air at the top has greater refractive index than hotter air just above the road.

• Light travels faster through the thinner hot air than the denser cool air above it.
• On hot days, the temperature decreases with height.
• Thus the refractive index of air increases with height.
• When the light from a tall object such as tree or from the sky passes, through a medium just above the road whose refractive index decreases towards ground, suffers refraction and takes a curved path because of total internal reflection.
• This refracted light reaches the observer in a direction shown as in second figure.
• This appears to the observer that the ray is reflected from ground.
• Hence we will see water on road, which is the virtual image of sky and an inverted image of tree on the road.
• Such virtual images of distant high objects cause the optical illusion called ‘mirage’.

Question 7.
How do you verify experimentally that \(\frac{\sin i}{\sin r}\) is a constant? (AS1)
(OR)
Explain the experiment that shows the relation between angle of incidence and angle of refraction through figure.
(OR)
Write an experiment to obtain the relation between angle of incidence and angle of refraction.
Answer:
Aim:
Identifying relation between angle of incidence and angle of refraction.

Materials required :
A plank, white chart, protractor, scale, small black painted plank, a semi-circular glass disc of thickness nearly 2 cm pencil and laser light.

Procedure :

1. Take a wooden plank which is covered with white chart.
2. Draw two perpendicular lines, passing through the middle of the paper as shown in the figure (a).
3. Let the intersecting point be O.
4. Mark one line as NN which is normal to the another line marked as MM.
5. Here MM represents the line drawn along the interface of two media and NN represents the normal drawn to this line at ‘O’.
6. Take a protractor and place it along NN in such a way that its centre coincides with ‘O’ as shown in figure (b).
7. Then mark the angles from 0° to 90° on both sides of the line NN.
8. Repeat the same on the other side of the line NN.
9. The angles should be represented on circular line.
10. Now place semi circular glass disc so that its diameter coincides with the interface line (MM) and its centre coincides with the point O.
11. Take the laser light and send it along NN in such a way that the laser propagates from air to glass through the interface at point O and observe the way of laser light coming from other side of disc.
12. There is no deviation.
13. Send Laser light along a line which makes 15° (angle of incidence) with NN and see that it must pass through point O.
14. Measure its corresponding angle of refraction.
15. Repeat the experiment with angle of incidences of 20°, 30°, 40°, 50° and 60° and note the corresponding angles of refraction.

Observation :

• Find sin i, sin r for every i and r note down the values in table.

• Evaluate \(\frac{\sin i}{\sin r}\) for every incident angle i.
• We get \(\frac{\sin i}{\sin r}\) as constant.
• That is the relationship between angle of incidence and angle of refraction.
• The ratio of sin i and sin r is called refractive index.

Question 8.
Explain the phenomenon of total internal reflection with one or two activities. (AS1)
Answer:
Procedure :

1. Place the semi-circular glass disc in such a way that its diameter coincides with interlace line MM and its center coincides with point O’.
2. Now send light from the curved side of the semicircular glass disc.
3. The light travels from denser medium to rarer medium.
4. Start with angle of incidence (i), equals to 0° and observe for refracted on other side of the disc.
5. It does not deviate into its path when entering rarer medium.
6. Send laser light along angles of incidence 5°, 10°, 15°, etc. and measure the angle of refraction.
7. And tabulate the results in the given table.

Observation :

• Make a table shown below and note the values ‘i’ and ‘r’.

• At particular angle of incidence, the refracted ray does not come out but grazes the interface separating the air and glass. This angle is called critical angle.
• When the angle of incidence is greater than critical angle, the light ray gets reflected into denser medium at the interface, i.e. light never enters rarer medium. This phenomenon is called total internal reflection.

Question 9.
How do you verify experimentally that the angle of refraction is more than angle of incidence when light rays travel from denser to rarer medium? (AS1)
(OR)
When the light rays travel from denser to rarer medium, how can you explain, the angle of refraction is more than angle of incidence experimentally?
Answer:
Procedure :

• Take a metal disc. Use a protractor and mark angles along its edge as shown in the figure.
• Arrange two straws at the centre of the disc, in such a way that they can be rotated freely about the centre of the disc.
• Adjust one of the straws to make an angle 10°.
• Immerse half of the disc vertically into the water, filled in a transparent vessel. While dipping, verify that the straw at 10° must be inside the water.
• From the top of the vessel, try to view the straw which is inside the water as shown in the figure.
• Then adjust the other straw which is outside of the water until both straws look like they are in a single straight line.
• Then take the disc out of the water and observe the two straws on it. You will find that they are not in a single straight line.
• Measure the angle between the normal and second straw. Note the values in the following table.

• Do the same for various angles and find the corresponding angles of refraction and note them in the table.

Observation :
We will find the angle of refraction is more than angle of incidence.
i. e., r > i.

Conclusion :
When light travels from denser (water) to rarer (air) it bends away from the normal.

Question 10.
Take a bright metal ball and make it black with soot in a candle flame. Immerse it in water. How does it appear and why? (Make hypothesis and do the above experiment) (AS2)
Answer:

• The black metallic .ball appears to be raised up in the water because the path of the ray changes its direction at the interface, separating the two media, i.e., water and air.
• This path is chosen by light ray so as to minimize time of travel between ball and eye.
• This can be possible only when the speed of light changes at interface of two media.
• In another way the speed of light is different in different media.

Hypothesis :
Speed of light changes when it travels from one medium to another medium.

Question 11.
Take a glass vessel and pour some glycerine into it and then pour water up to the brim. Take a quartz glass rod. Keep it in the vessel. Observe the glass rod from the sides of the glass vessel.
1) What changes do you notice?
2) What could be the reasons for these changes? (AS2)
Answer:

1. We cannot see the glass rod in glycerine but we can see the rod in water.
2. We can also observe an apparent image of glass rod in water.
3. Reasons:
   i) Glycerine has essentially same refractive index as glass.
   ii) So, any light passing through these is bent equally.
   iii) Since both are transparent, it is not possible for our eye to distinguish the boundary by a change in the angle of reflection, and the glass seems to vanish.
   iv) But, the refractive index of glass and water are different.
   v) So the glass rod is visible to our eye in water. .

Question 12.
Do Activity-7 again. How can you find critical angle of water? Explain your steps briefly. (AS3)
Answer:

Procedure:

1. Take a cylindrical transparent vessel.
2. Place a coin at the bottom of the vessel.
3. Now pour water until you get the image of the coin on the water surface.
4. This is due to total internal reflection.

Critical angle of water :

1. Refractive index of water = 1.33
2. The sine of critical angle of water = \(\frac{1}{\text { Refractive index }}\)
3. Sin C = \(\frac{1}{\text { 1.33 }}\) ⇒ sin C = 0.7518.
   ∴ C = 8.7°
4. ∴ The critical angle of water = 48.7°.

Question 13.
Collect the values of refractive index of the following media. (AS4)

Water, coconut oil, flint glass, crown glass, diamond, benzene and hydrogen gas.

Answer:

Medium	Refractive Index
1. Water	1.33
2. Coconut oil	1.445
3. Flint glass	1.65
4. Crown glass	1.52
5. Diamond	2.42
6. Benzene	1.50
7. Hydrogen gas	1.000132

Question 14.
Collect information on working of optical fibres. Prepare a report about various uses of optical fibres in our daily life. (AS4)
(OR)
What do you know about the working of optical fibres and make a report of various uses of optical fibres in our daily life?
(OR)
How are the optical fibres working? What are the various uses of optical fibres in our daily life?
Answer:
1) An optical fibre is very thin fibre made of glass or plastic having radius about a micrometer (10-6 m).
2) A bunch of such thin fibres form a light pipe.

Working :
1. Optical fibre having three parts-namely core (n = 1, 7), clading (n = 1, 6) and shielding.
2. The ray of light AB gets refracted at point ‘B’ into core and incident at ‘C’ with angle of incidence i (i > c).

3. The angle of incidence is greater than the critical angle and hence total internal reflection takes place.
4. The light is thus transmitted along the fibre.
5. The optical fibre is also based on ‘Fermat’s principle.

Uses :

1. Optical fibres are used in ‘endoscopy’ to see the internal organs like throat, stomach, intestines, etc.
2. Optical fibres are used in transmitting communication signals through light pipes.
3. Optical fibres are used in international telephone cables laid under the sea, in large computer networks, etc.
4. In optical fibre about 2000 telephone signals appropriately mixed with light waves may be simultaneously transmitted through a typical optical fibre.

Question 15.
Take a thin thermocol sheet. Cut it in circular discs of different radii like 2 cm, 3 cm, 4 cm, 4.5 cm, 5 cm etc. and mark centers with sketch pen. Now take needles of length nearly 6 cm. Pin a needle to each disc at its centre vertically. Take water in a large opaque tray and place the disc with 2 cm radius in such a way that the needle is inside the water as shown in figure. Now try to view the free end (head) of the needle from surface of the water.

1) Are you able to see the head of the needle?
Now do the same with other discs of different radii. Try to see the head of the needle, each time.
Note : The position of your eye and the position of the disc on water surface should not be changed while repeating the Activity with’other discs.
2) At what maximum radius of disc, were you not able to see the free end of the needle ?
3) Why were you not able to view the head of the nail for certain radii of the discs ?
4) Does this Activity help you to find the critical angle of the medium (water) ?
5) Draw a diagram to show the passage of light ray from the head of the nail in different situations. (AS4)
Answer:

1. Yes, we can see head of the needle.

2. Height of the pin = 6 cm
Radius of the disc = x cm
Critical angle of water = C = 48.7°
Tan C = 48.7°
\(\frac{x}{6}\) = 1.138 ⇒ x = 6.828 cm
So, at radius of 6.8 cm we cannot see the free end of the needle.

3. Because the light rays coming from object undergoing total internal reflection by touching the surface of disc.

4. Yes, we can find critical angle.
Refractive index of air (n₂) = 1.003 ; Refractive index of water (n₁) = 1.33
Sin C = \(\frac{n_{2}}{n_{1}}=\frac{1.003}{1.33}\) = 0.7541 ⇒ C = 48.7°

5.

Question 16.
Explain the refraction of light through the glass slab with a neat ray diagram. (AS5)
(OR)
Draw a glass slab diagram and explain the refraction of light through glass slab.
(OR)
Write the procedure of a lab Activity to understand lateral shift of light rays through a glass slab.
(OR)
How can you find lateral shift using glass slab?
Answer:
Aim :
A) Determination of position and nature of image formed by a glass slab.
B) Understanding lateral and vertical shift.
C) Determination of refractive index of given glass slab.

Materials required :
Plank, chart paper, clamps, scale, pencil, thin glass slab and pins.

Procedure :

1. Place a piece of chart on a plank. Clamp it. Place a glass slab in the middle of the paper.
2. Draw border line along the edges of the slab by using a pencil. Remove it. You will get a figure of a rectangle.
3. Name the vertices of the rectangle as A, B, C and D.
4. Draw a perpendicular at a point on the longer sides (AB) of the rectangle.
5. Now draw a line, from the point of intersection where side AB of rectangle and perpendicular meet, in such a way that it makes 30° angle with the normal.
6. This line represents the incident ray falling on the slab and the angle it makes with normal represents angle of incidence.
7. Now place the slab on the paper in such a way that it fits in the rectangle drawn. Fix two identical pins on the line making 30° angle with normal, such that they stand vertically with same height.
8. By looking at the two pins from the other side of the slab, fix two pins in such a way that all pins appear to be along a straight line.
9. Remove the slab and take out pins. Draw a straight line by joining the dots formed by the pins up to the edge CD of the rectangle.
10. This line represents emergent ray of the light.
11. Draw a perpendicular to the line CD where our last line drawn meets the line CD.
12. Measure the angle between emergent ray and normal.
13. This is called angle of emergence.
14. The angle of incidence and angle of emergence are equal.
15. Incident emergent rays are parallel.
16. The distance between the parallel rays is called shift.

Question 17.
Place an object on the table. Look at the object through the transparent glass slab. You will observe that it will appear closer to you. Draw a ray diagram to show the passage of light ray in this situation. (AS5)
Answer:

Question 18.
What is the reason behind the shining of diamond and how do you appreciate it? (AS6)
(OR)
For which reason is the diamond shining and how is it appreciable?
Answer:

• The critical angle of diamonds is very low, i.e., 24.4°.
• So if a light ray enters diamond, it undergoes total internal reflection.
• It makes the diamond shine brilliant.
• So total internal reflection is main cause of brilliance of diamonds.
• Majority of people are attracted towards diamonds due to this property.
• So we have to thoroughly appreciate total internal reflection for brilliance of diamonds.

Question 19.
How do you appreciate the role of Fermat’s principle in drawing ray diagrams? (AS6)
(OR)
How do you admire the role of Fermat’s principle in drawing ray diagrams? Fermat’s principle: The light ray always travels in a path which needs shortest possible time to cover distance between two points.
This principle has lot of importance on optics. This is used in

1. Laws of reflection (i.e., angle of incidence = angle of reflection)
2. Laws of refraction (Snell’s law)
3. To derive refractive index of a medium.
4. To derive refractive index of glass slab.
   So, I appreciate the Fermat’s principle.

Question 20.
A light ray is incident on air-liquid interface at 45° and is refracted at 30°. What is the refractive index of the liquid? For what angle of incidence will the angle between reflected ray and refracted ray be 90°? (AS7)
Answer:
i) Given that angle of incidence (i) = 4S°
angle of refraction (r) = 30°

ii) Given that angle between reflected and refracted ray is 90°.
We know angle of incidence = angle of reflection
∴ Angle of refraction (r) = 90 – angle of incidence
= 90 – i

Critical angle = 54.7°. This angle is also known as polarising angle.

Question 21.
Explain why a test tube immersed at a certain angle in a tumbler of water appears to have a mirror surface from a certain viewing position. (AS7)
Answer:
When a test tube is immersed at a certain angle in a tumbler of water appears to have
a mirror surface from a certain viewing positions due to total internal reflection.

Explanation :

• The critical angle for glass is 42°.
• The glass and air in test tube works as denser and rarer mediums.
• The rays of light while travelling through water strike glass – air interface of test tube at an angle of more than 42° (i > c) they get totally internal reflected as shown figure.
• When these reflected rays reach the eye, they appear to come from the surface of test tube itself.
• Now the test tube appears like silvary.

Question 23.
In what cases does a light ray not deviate at the interface of two media? (AS7)
Answer:

1. When a light ray incident is perpendicular to the interface of surface, it does not undergo deviation.
2. When a light ray incident is more than critical angle, it does not undergo deviation (refraction) but it undergoes reflection to come back into the original medium.

Question 25.
When we sit at camp fire, objects beyond the fire seen swaying. Give the reason for it. (AS7)
(OR)
What are the reasons for the objects beyond the fire seen swaying, when we sit at camp fire?
Answer:

• The temperature of the surrounding air changes due to convection of heat by the camp fire.
• This leads to chang in density and refractive index of air, continuously.
• The continuous change in refractive index of air changes the refracted path of the light ray.
• This is the cause for swaying of an object.

Question 26.
Why do stars appear twinkling? (AS7)
(OR)
What is the reason for the appearance of stars like twinkling?
Answer:

• The twinkling of a star is due to atmospheric refraction of star light.
• The atmosphere consists of a number of layers of varying densities.
• When light rays coming from a star pass through this layers and undergo refraction for several times.
• Thats why stars appear twinkling.

Question 27.
Why does a diamond shine more than a glass piece cut to the same shape? (AS7)
(OR)
What is the reason for shining of diamond brightly as compared to glass piece cut?
Answer:

• The critical angle of a diamond is very low (i.e., 24.4°).
• So if a light ray enters a diamond it definitely undergoes total internal reflection.
• Whereas it is not possible with glass piece cut to the same shape.
• So diamond shines more than a glass piece.

Fill In The Blanks

1. At critical angle of incidence, the angle of refraction is ……………… .
2. n₁ sin i = n₂ sin r, is called ……………… .
3. Speed of light in vacuum is ……………… .
4. Total internal reflection takes place when a light ray propagates from …………. to …………… medium.
5. The refractive index of a transparent material is 3/2. The speed of the light in that medium is …………… .
6. Mirage is an example of ……………… .
Answer:

1. 90°
2. Snell’s law
3. 3 × 10⁸ m/s
4. denser, rarer
5. 2 × 10⁸ m/s
6. optical illusion / total internal reflection

Multiple Choice Questions

1. Which of the following is Snell’s law?

Answer:
B)

2. The refractive index of glass with respect to air is 2. Then the critical angle of glass air interface is ………………….
A) 0°
B) 45°
C) 30°
D) 60°
Answer:
C) 30°

3. Total internal reflection takes place when the light ray travels from …………….. .
A) rarer to denser medium
B) rarer to rarer medium
C) denser to rarer medium
D) denser to denser medium
Answer:
C) denser to rarer medium

4. The angle of deviation produced by the glass slab is …………… .
A) 0°
B) 20°
C) 90°
D) depends on the angle formed by the light ray and normal to the slab
Answer:
D) depends on the angle formed by the light ray and normal to the slab

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Additional Questions and Answers

Question 1.
Derive Snell’s law.
(OR)
Prove n₁ sin i = n₂ sin r.
(OR)
Derive the Snell’s formula from Fermat’s principle.
(OR)
Derive the formula in realtion with and of incidence and angle of refraction.
Answer:
Let X be the path and A be the point above X and B be the point below X.
Now, we have to find the way from A to B.

1. Let us try to calculate how long it would take to go from A to B by the two paths through point D and another through point C.
2. If we draw a perpendicular DE, between two paths at D, we see that the path on line is shortened by the amount EC.
3. On the other hand, in the water, by drawing corresponding perpendicular CF we find that we have to go to the extra distance DF in water. These times must be equal since we assumed there was no change in time between two paths.
4. Let the time taken by the man to travel from E to C and D to F be ∆t and v₁ and v₂ be the speeds of the running and swimming. From figure we get,
   EC = v₁ ∆t and DF = v₂ ∆t
   ⇒ \(\frac{\mathrm{EC}}{\mathrm{DF}}=\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}}\) ………….. (1)
5. Let i and r be the angles measured between the path ACB and normal NN, perpendicular to shore line X.

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces InText Questions and Answers

10th Class Physics Textbook Page No. 56

Question 1.
Why should you see a mirage as a flowing water?
Answer:

• A mirage is a naturally occuring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky.
• As light passes from colder air (higher place) to warmer air (lower place), the light ray bends away from the direction of the temperature gradient.
• Once the rays reach the viewer’s eye, the visual cortex interprets it as if it traces back along a perfectly straight “line of sight”. However this line is at a tangent to the path the ray takes at the point it reaches the eye.
• The result is that an “inferior image ” of the sky above appears on the ground.
• The viewer may incorrectly interprets this sight as water that is reflecting the sky, which is to the brain, a more reasonable and common occurrence.

Question 2.
Can you take a photo of a mirage?
Answer:

• Yes, I can take a photo of a mirage.
• Our eye can catches the total internal reflected rays.
• So, camera lens also catches the same.

10th Class Physics Textbook Page No. 46

Question 3.
What difference do you notice in fig 2(a) and Fig 2(b) with the respect to refracted rays?
(OR)
Draw the ray diagram of refraction in between denser and rarer medium.

Answer:
In figure 2(a) the light ray bends towards normal whereas in 2(b) the light ray bends away from the normal.

Question 4.
Is there any relation between behaviour of refracted rays and speed of the light?
Answer:
Yes. The speed of light changes when it travels from one medium to another medium. So the light may bend towards normal or away from normal.

10th Class Physics Textbook Page No. 47

Question 5.
Why db different material media possess different values of refractive indices?
Answer:
Refractive index depends on nature of material. So different media have different values of refractive indices.

10th Class Physics Textbook Page No. 48

Question 6.
On what factors does the refractive index of a medium depend?
Answer:
Refractive index depends on (1) Nature of material and (2) Wavelength of light used.

10th Class Physics Textbook Page No. 49

Question 7.
Can we derive the relation between the angle of incidence and the angles of refraction theoretically?
Answer:
Yes, we can derive the relation between angle of incidence and angles of refraction theoretically. We can get nt sin i = n2 sin r.

10th Class Physics Textbook Page No. 53

Question 8.
Is there any chance that angle of refraction is equal to 90° ? When does this happen?
Answer:
Yes, when angle of incidence is equal to critical angle then angle of refraction is equal to 90°.

10th Class Physics Textbook Page No. 54

Question 9.
What happens to light when the angle of incidence is greater than critical angle?
Answer:
When the angle of incidence is greater than critical angle, the light ray gets reflected into denser medium at the interface, i.e., light never enters rarer medium. This phenomenon is called total internal reflection.

10th Class Physics Textbook Page No. 57

Question 10.
How does light behave when a glass slab is introduced in its path?
Answer:
The light ray undergoes refraction two times.

10th Class Physics 5th Lesson Refraction of Light at Plane Surfaces Activities

Activity – 1

Question 1.
Procedure :
Take some water in a glass tumbler. Keep a pencil in it. See the pencil from one side of glass and also from the top of the glass.
Observation:

1. How does it look?
Answer:
From the side it appears to be bent. From the top it appears as it is raising.

2. Do you find any difference between two views?
Answer:
Yes, the position of pencil is different.

Activity – 2

Question 2.
Procedure :

1. Go to a long wall (of length of 30 feet) facing the Sun. Go to the one end of a wall and ask someone to bring a bright metal object near the other end of the wall.
2. When the object is few inches from the wall, it will distort and we will see a reflected image on the wall as though the wall were a mirror.

Observation:

Why is there an image of the object on the wall?
Answer:
The image is due to refraction of light.

Activity-3 Refraction

Question 3.
Procedure: –

1. Take a shallow vessel with opaque walls such as a mug, a tin or a pan.
2. Place a coin at the bottom of the vessel.
3. Move away from the vessel until we cannot see the coin (fig. 2). Ask someone to fill the vessel with water. When the vessel is filled with water the coin comes back into view (fig. 3).

1. Why are you able to see the coin when the vessel is filled with water?
Answer:
The ray of light originated from the coin does not reach your eye when the vessel is empty. Hence you are not able to see the coin. But the coin becomes visible after the vessel is filled with water.

2. How is it possible? Do you think that the ray reaches your eye when the vessel is filled with water?
Answer:
Yes, it reaches the second instance.

3. What happens to the light ray at interface between water and air?
Answer:
It bends towards the normal.

4. What could be the reason for this bending of the light ray in the second instance?
Answer:
It is based on Fermat’s principle, which states that the light ray always travels in a path which needs shortest possible time to cover the distance between the two points.

Activity – 4

Question 4.
Prove that when light ray travels from denser to rarer medium it bends away from the normal.
Answer:


Procedure :

1. Take a metal disc. Use protractor and mark angles along its edge as shown in the figure.
2. Arrange two straws from the centre of the disk.
3. Adjust one of the straws to the angle 10°.
4. Immerse half of the disc vertically into the water, filled in a transparent vessel.
5. Inside the water the angle of straw should be at 10°.
6. From the top of the vessel try to view the straw which is inside the water.
7. Then adjust the other straw which is outside the water until both straws are in a single straight line.
8. Then take the disc out of the water and observe the two straws on it.
9. We will find that they are not in a single straight line.
10. It could be seen from the side view while half of the disc is inside the water.
11. Measure the angle between the normal and second straw. Draw table for various angles and corresponding angles of refraction.

Observation :
We observe that ‘r’ is greater than ‘i’ in all cases and when light travels from
denser to rarer medium it bends away from the normal.

Activity – 6

Question 5.
Why can we not see a coin placed in water from the side of glass?
Answer:
Procedure :

1. Take a transparent glass tumbler and coin.
2. Place a coin on a table and place glass on the coin.
3. Observe the coin from the side of the glass. We can see the coin.
4. Now fill the glass with water and observe the coin from the side of the glass tumber.
5. Now we cannot see the coin because the coin rises up due to refraction.

Activity – 7

Question 7.
Why can we see the coin in water from top? What is the phenomenon behind that?
Answer:

Procedure :

1. Take a cylindrical transparent vessel. Place a coin at the bottom of the vessel.
2. Now pour water until we will get the image of the coin on the water surface.
3. This is due to total internal reflection.

Activity – 8

Question 8.
Write an Activity to find refractive index of glass slab by calculating vertical shift.
(OR)
Explain the experiment with glass slab in determination of refraction through vertical shift.
Answer:

Procedure :

1. Take a glass slab and measure the thickness of the slab.
2. Take a white chart and fix it on the table.
3. Place the slab in the middle of the chart.
4. Draw line around it.
5. Remove the slab from its place.
6. The lines form a rectangle. Name the vertices of it as A. B, C and D. ‘
7. Draw a perpendicular to the longer line AB of the rectangle at any point on it.
8. Place slab again in the rectangle ABCD.
9. Take a needle. Place at a point P in such a way that its length is parallel to the AB on the perpendicular line at a distance of 20 cm from the slab.
10. Now take another needle and by seeing at the first needle from the other side of the slab, try to keep the needle so that it forms a straight line with the first needle. 1 1)
11. Remove the slab and observe the positions of the needles.
12. They are not in same line.
13. Draw a perpendicular line from the second needle to the line on which the first needle is placed.
14. Take the intersection point as Q.
15. The distance between P and Q is vertical shift.
16. We will get the same vertical shift placing needle at different distances.
17. 

AP State Board Syllabus AP SSC 10th Class Biology Important Questions Chapter 1 Nutrition.

AP State Syllabus SSC 10th Class Biology Important Questions 1st Lesson Nutrition

10th Class Biology 1st Lesson Nutrition 1 Mark Important Questions and Answers

Question 1.
Define photosynthesis. (OR) What is photosynthesis?
Answer:
Photosynthesis is the process by which plants containing the green pigment called chlorophyll which build up complex organic molecules from relatively simple inorganic ones using sun light as an energy source.

Question 2.
What is the balanced equation to show the process of photosynthesis?
Answer:

Question 3.
Bhumika told that “If there were no green plants, all life on the earth would come to an end” Comment.
Answer:
All the living organisms on the earth depends on the plants either directly or indirectly for the food and oxygen.

Question 4.
Which disease occurs in child when there is an immediate second pregnancy or repeated child births in a mother?
Answer:
Marasmus

Question 5.
Give two examples for nutritional deficiency diseases.
Answer:
Nutritional deficiency diseases: Kwashiorkor, Marasmus, Beri-Beri, Glossitis, Pellagra, Anemia, Scurvy, Rickets, etc.

Question 6.
Your neighbour’s children appear with swollen legs, hands and other body parts. They have dry skin and frequently suffering from Diarrhoea. What are the reasons for it ? What suggestions do you give to their parent ?
Answer:
The children appear with swollen legs, hands and other body parts. They have dry skin and suffering from diarrhoea.
The reason for it is malnutrition and they are suffering from Kwashiorkor and Marasmus diseases.
They are advised to take proteins and calorie rich foods like liver, meat, eggs, milk, fruits, cereals and leafy vegetables.

Question 7.
What suggestions do you give to your friend suffering from constipation?
Answer:
Constipation can often be avoided by
a) having plenty of roughages in our daily diet. Ex : Leafy vegetables, beans, cabbage, etc.
b) drink plenty of water daily.
c) avoid junk food,
d) swallow the food only after its thorough mastication.

Question 8.
Which organelle of the leaf absorbs energy from the sunlight for photosynthesis ?
Answer:
Chloroplast.

Question 9.
Which gas is evolved in the diagram experiment? How can this gas be tested for confirmation?

Answer:
i) Oxygen gas is evolved in this experiment.
ii) If the burning splinter is kept near the mouth of the test tube, it burns brightly.

Question 10.
Classify the following vitamins into water soluble and fat soluble
i) Riboflavin ii) Retinol iii) Tocoferol iv) Thiamin
Answer:
Water soluble vitamins : Riboflavin (B₂), Thiamin (B₁)
Fat soluble vitamins : Retinol (A), Tocoferol (E)

Question 11.
Prepare your own tabular column to get information about food deficiency diseases from a doctor.
Answer:

S.No.	Name of the disease	Symptoms	Deficiency due to which nutrient
1.	Kwashiorkor	Hands and legs swollen, fluffy face, loose motions.	Protein deficiency
2.	Marasmus	Lean, weak, swollen joints, no development in muscles, loose motions.	Both proteins and calories deficiency.

Question 12.
Why is KGH used in Mohl’s half leaf experiment? (OR)
Why do we use KOH solution in Mohl’s half-leaf experiment?
Answer:
1) We conducted Mohl’s half leaf experiment to prove CO₂ is essential for photosynthesis.
2) So KOH is used in this experiment to absorb the CO₂ present inside the bottle.

Question 13.
What questions will you ask a doctor to know about malnutrition ?
Answer:

1. What is malnutrition?
2. What are the causes for malnutrition?
3. What are the different types in malnutrition?
4. How can we overcome the malnutrition?
5. What are the reasons for malnutrition in our country?

Question 14.
Name the vitamin which is synthesized by the bacteria present in the human intestine.
Answer:
B₁₂ (Cyanocobalamine) is the vitamin which is synthesized by the bacteria present in the human intestine.

Question 15.
Which digestive juice doesn’t contain enzymes ?
Answer:
Bile juice which is produced by liver doesn’t contain enzymes. But it converts fats into small globules. This process is called emulsification.

Question 16.
One student takes high calorie food. Another student takes less calorie food. But both are affected with diseases. Name the diseases by which they are affected.
Answer:
Student takes high calorie food affected by – Obesity.
Student takes less calorie food affected with – Marasmus.

Question 17.
Mention the two chemicals which you have used in an experiment to test the presence of starch in the leaf.
Answer:
The chemicals used in an experiment to test the presence of starch in the leaf are

1. Methylated spirit
2. Iodine solution.

Question 18.
18. Write two slogans for campaign on Mal-nutrition.
Answer:

1. Be cool and say no to fast food.
2. Be smart – Eat smart
3. Eat healthy – Look healthy – Feel healthy

Question 19.
Identify the two parts A and B indicated in the given figure.

Answer:
A – Stomach
B – Large intestine

Question 20.
Doctors advise not to eat food items at the time of fever. What are the reasons for this ?
Answer:

1. At the time of fever body temparature is high.
2. At that time digestive enzymes do not properly work to digest food.
3. That’s why doctors advise not to eat food items at the time of fever.

Question 21.
If we chew the grains like wheat, jowar, rice we feel sweet. Why?
Answer:

1. The grains like wheat, jowar, rice contain carbohydrates.
2. Ptyalin acts on them and coverts them into sugars. So we feel sweet.

Question 22.
What teeth you use when you eat peas and banana? Why?
Answer:

1. Premolars and molars are used when we eat peas and banana.
2. Their function is to chew and grind the seed and food material.

Question 23.
What is autotrophic nutrition?
Answer:
It is a type of nutrition in which an organism makes its own food from the simple inorganic materials like carbon dioxide and water using light as source of energy.

Question 24.
What is nutrition ?
Answer:
Nutrition: Nutrition is the process of intake or procurement of nutrients.

Question 25.
What are the main modes of nutrition ?
Answer:
Autotrophic nutrition and heterotrophic nutrition are the main modes of nutrition.

Question 26.
What are different types of heterotrophic nutrition ?
Answer:
Heterotrophic nutrition is of three types. They are:

1. Saprophytic nutrition
2. Parasitic nutrition and
3. Holozoic nutrition.

Question 27.
What are the symptoms of disease pellagra?
Answer:
Dermatitis, diarrhoea, loss of memory and scaly skin are the symptoms of disease pellagra.

Question 28.
Which vitamin deficiency causes Rickets ? What are its symptoms?
Answer:
Vitamin D Calciferol deficiency results in Rickets. The symptoms shown are improper formation of bones, knocknees, swollen wrists, delayed dentition, weak bones, etc.

Question 29.
For proper vision which vitamin is required? What is its chemical name?
Answer:
Vitamin A is required for proper vision. The chemical name of vitamin ‘A’ is Retinol.

Question 30.
What are the complex molecules produced by plants from simple Inorganic substances?
Answer:
Carbohydrates, proteins and lipids are produced from simple inorganic substances like water and CO₂.

Question 31.
What are the essential factors required for photosynthesis?
Answer:
Carbon dioxide, water, chlorophyll and sunlight are the essential factors required for photosynthesis.

Question 32.
What is the equation for photosynthesis proposed by C.B.Van Neil in the year 1931?
Answer:

Question 33.
In which form are carbohydrates stored in plants?
Answer:
Carbohydrates are stored in plants in the form of starch.

Question 34.
What is the reagent that is used to test the presence of starch in leaves?
Answer:
The reagent that is used to test the presence of starch in leaves is Iodine solution. The colour of the leaf will turn to blue-black in colour.

Question 35.
Who found that water was essential for the increase of plant mass?
Answer:
Von Helmont found that water was essential for increase of plant mass in the year 1648.

Question 36.
Who performed series of experiments in 1770 to reveal the role of air in growth of green plants?
Answer:
Joseph Priestly performed series of experiments in 1770 to reveal the role of air in growth of green plants.

Question 37.
What is the role of potassium hydroxide solution kept inside the glass bottle in the Mohl’s half leaf experiment?
Answer:
Potassium hydroxide solution kept inside the glass bottle in the Mohl’s half leaf experiment absorbs the carbon dioxide present inside the bottle.

Question 38.
Who found that gas bubbles liberated from hydrilla plant contain the gas oxygen?
Answer:
Jan Ingenhousz in 1779 found that the gas bubbles liberated from hydrilla plant contain the gas oxygen.

Question 39.
Who coined the term chlorophyll for the extract of green coloured substance from the leaf?
Answer:
Pelletier and Caventou in the year 1817 coined the term chlorophyll for the extract of green coloured substance from the leaf.

Question 40.
Chloroplast is formed by how many membranes?
Answer:
Chloroplast is formed by 3 membranes.

Question 41.
What is grana?
Answer:
Grana : The stacked sac like structures formed by the third layer of chloroplasts is called grana.

Question 42.
What is the function of stroma?
Answer:
It is believed to be responsible for enzymatic reactions leading to the synthesis of glucose, which inturn join together to form starch.

Question 43.
What is stroma?
Answer:
Stroma : The fluid filled portion of chloroplast is called as stroma.

Question 44.
What are the two major phases found in photosynthesis?
Answer:
The two major phases found in photosynthesis are:

Question 45.
Why is light reaction phase called photochemical phase?
Answer:
A series of chemical reactions occur in a very quick succession initiated by light and therefore the phase is technically called the photochemical phase.

Question 46.
Where does the light reaction take place?
Answer:
The light reaction takes place in chlorophyll containing thylakoids called grana of Chloroplasts.

Question 47.
What are the end products of light reaction?
Answer:
The end products of light reaction are O₂, ATP and NADPH.

Question 48.
What are called the assimilatory powers?
Answer:
ATP and NADPH formed at the end of the light reaction are called assimilatory powers.

Question 49.
What are dark reactions?
Answer:
Dark reactions: The reactions that occur in both presence or absence of light are called dark reactions. The occurance of dark reaction is independent of light.

Question 50.
Who observed dark reactions?
Answer:

1. The entire series of reactions involved in the conversion of CO₂ to glucose were identified by Melvin Calvin.
2. The dark reactions are also called as Calvin Cycle.

Question 51.
What is Calvin cycle?
Answer:
Calvin cycle: The cycle of reactions in fixation of carbon dioxide to glucose is called Calvin cycle.

Question 52.
How is glucose produced during dark reaction?
Answer:
In the dark reaction, the hydrogen of the NADPH is used to combine with CO₂ by utilizing ATP energy and ultimately produce glucose.

Question 53.
Write some of the events that occur in the chloroplasts during photosynthesis.
Answer:

1. Conversion of light energy to chemical energy.
2. Splitting of water molecule.
3. Reduction of carbon dioxide to carbohydrates.

Question 54.
What is photolysis of water? Which gas is released?
Answer:
Photolysis of water:

1. Photolysis of water Splitting of water molecule by light activated chlorophyll molecule is known as photolysis of water.
2. Oxygen is released during (photosynthesis) photolysis of water.

Question 55.
In which cells of the leaves photosynthesis takes place?
Answer:
The mesophyll cells of leaf containing palisade and spongy tissue photosynthesis takesplace.

Question 56.
What is the ultimate source of energy?
Answer:
The ultimate source of energy is the Sun.

Question 57.
What are guard cells?
Answer:
Guard cells: The two kidney shaped cells which surrounds the stoma are called guard cells.

Question 58.
How does CO₂ enter into leaf?
Answer:
CO₂ present in the atmosphere enters through stomata into the cells of leaf by diffusion.

Question 59.
What is the first stable product formed in dark reaction or photosynthesis?
Answer:
Phosphoglyceric acid or PGA is the first stable product formed in dark reaction or photosynthesis.

Question 60.
Why ATP and NADPH are required in photosynthesis?
Answer:
ATP and NADPH are required for the utilization of carbon dioxide and formation of glucose during photosynthesis.

Question 61.
Why chloroplasts are green in colour?
Answer:
Chloroplasts are green in colour due to the presence of a green colouring pigment called chlorophyll.

Question 62.
What are the examples for parasitic organisms?
Answer:
The examples for parasitic organisms are cuscuta (plant), lice, leeches and tapeworms (animals).

Question 63.
How does amoeba take food into the body?
Answer:
Amoeba takes in food using temporary finger like extensions called pseudopia of the cell surface.

Question 64.
How does paramoecium take food?
Answer:
Food is moved to the cytosome by the movement of cilia which covers the entire surface of the cell where the food is ingested.

Question 65.
What is ingestion?
Answer:
Ingestion : The process of taking food into the body is called ingestion.

Question 66.
Name the three pairs of salivary glands. What is the enzyme secreted by them?
Answer:

1. The three pairs of salivary glands in mouth are :
   i) Parotid glands
   ii) Submandibular glands and
   iii) Sublingual glands.
2. The enzyme secreted by salivary glands is amylase (ptyalin).

Question 67.
What is the role of amylase in digestion of food?
Answer:
Amylase helps in the breakdown of complex carbohydrates to simple ones.

Question 68.
What is digestion?
Answer:
Digestion : The process of breaking down of complex food substances into simple substances so that they can be used by the body with the help of enzyme is called digestion.

Question 69.
How does the food from oesophagus move into the stomach?
Answer:
Food passes through oesophagus by wave like movements called peristaltic movements and reaches the stomach.

Question 70.
What is chyme?
Answer:
Chyme : Chyme is a soft slimy substance of food in which some proteins and carbohydrates have broken down.

Question 71.
What is the function of sphincter muscle present at the exit of stomach?
Answer:

1. The sphincter muscle is responsible for regulating the openings of the stomach into small intestine.
2. So that only small quantities of the food material may be passed into the small intestine from the stomach at a time.

Question 72.
What does the gastric juice contain?
Answer:
The gastric juice secreted by the walls of stomach contains Hydrochloric acid, protein digesting enzyme, pepsin and mucus.

Question 73.
What makes the internal condition of the intestine gradually to a basic or alkaline one?
Answer:
Liver and pancreatic juice make the internal condition of the intestine gradually to a basic or alkaline one.

Question 74.
What is emulsification?
Answer:
Emulsification : Fats are digested by converting them into small globule like forms by the help of bile juice secreted from liver. This process is known as emulsification.

Question 75.
For what intestinal juice secreted by small intestine is responsible?
Answer:
The enzymes present in intestinal juice finally convert the protein to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

Question 76.
What are the enzymes that act on proteins?
Answer:
Pepsin and Trypsin are the enzymes that act on proteins. Both these enzymes convert proteins to peptones.

Question 77.
What is absorption?
Answer:
Absorption : Transport of the products of digestion from the walls of the intestine into blood is called absorption.

Question 78.
What is defecation?
Answer:
Defecation: The passage of undigested material from the body by the way of anus is called defecation.

Question 79.
What are roughages in the food?
Answer:
Roughages are the fibres of either carbohydrates or fats which help in constipation.

Question 80.
What are the parts of human digestive system?
Answer:
Mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine, rectum and anus.

Question 81.
What is a balanced diet?
Answer:
Balanced diet: Diet containing nutrients in required amounts is known as balanced diet.

Question 82.
What are the nutrients present in balanced diet?
Answer:
Carbohydrates, proteins, fats, vitamins and mineral salts are the nutrients present in balanced diet.

Question 83.
What is malnutrition?
Answer:
Malnutrition : Eating of food that does not have one or more than one nutrients in required amount is known as malnutrition.

Question 84.
What are different types of malnutrition?
Answer:
Malnutrition is of three types. They are:

1. Calorie malnutrition
2. Protein malnutrition and
3. Protein calorie malnutrition.

Question 85.
What are the two sources of vitamins to our body?
Answer:
The two sources of vitamins to our body are one is diet and the other is bacteria present in the intestine synthesise enzymes and supply them to the body.

Question 86.
Vitamins are classified into how many groups?
Answer:
Vitamins are classified into two groups. They are fat soluble (eg : A, D, E and K) and water soluble (eg : B complex, Vitamin C).

Question 87.
What is the chemical name of vitamin B₁₂?
Answer:
The chemical name of vitamin B₁₂ is Cyanocobalamine.

Question 88.
Which vitamin deficiency causes sterility in males?
Answer:
Vitamin E. i.e., tocopherol deficiency causes sterility in males.

Question 89.
What is the name of vitamin ‘C’? Deficiency of vitamin ‘C’ causes which disease?
Answer:
The chemical name of vitamin ‘C’ is Ascorbic acid. Its deficiency results in Scurvy disease.

Question 90.
What are saprophytes?
Answer:
Saprophytes: Saprophytes are the organisms which obtain their food from dead plants, dead and decaying animal bodies and other organic matter. Eg: Fungi, many bacteria.

Question 91.
What is peristaltic movement?
Answer:
Peristaltic movement: The muscles present in the wall of oesophagus rhythmically contracts and relaxes. This produces an wave like movement known as a peristaltic movement.

Question 92.
Name the intestinal enzymes present in small intestine and what are their functions.
Answer:
Peptidases and sucrases are the enzymes present in the intestinal juice. Peptidases converts peptides to amino acids. Sucrase converts sucrose (cane sugar) into glucose.

Question 93.
Name the parts of small intestine.
Answer:
The anterior part of small intestine is called the duodenum, the middle part is the jejunum and the posterior part is called the ileum.

Question 94.
What is the enzyme present only in children?
Answer:
Renin is the enzyme present only in children. It helps in curdling of milk.

Question 95.
How many types of teeth are present in our mouth?
Answer:
Four types of teeth are present in our mouth. They are incisors, canine, premolars and molars.

Question 96.
What is the use of tongue?
Answer:
Tongue is useful for mixing and pushing the food in between teeth and helps to push into oesophagus.

Question 97.
What was the opinion of C.B. Van Neil on the equation for photosynthesis?
Answer:
For each molecule of carbohydrate formed, one molecule of water and one molecule of oxygen is also produced.

Question 98.
“Plants are capable of surviving under a range of situations.” How do you support this statement?
Answer:

1. Plants are capable of surviving under a range of situations.
2. They survive from very hot, dry and brightly lighted conditions to wet, humid and dimly lighted ones.
3. The requirement of light and other factors varies from one plant to other.

Question 99.
From where do we get energy to do work?
Answer:
We get energy to do work from the food we eat.

Question 100.
What did Priestly hypothesize on the experiment he conducted on the role of air in the growth of plants?
Answer:
Priestly hypothesized that plants restore to the air whatever breathing animals and burning candles remove.

Question 101.
How does gaseous exchange occur in plants?
Answer:
Gaseous exchange occurs in plants through the stomata present in leaves and also through the lenticels present on stems.

Question 102.
How do the aquatic plants acquire CO₂ to manufacture food?
Answer:
Aquatic plants utilizes or absorbs the carbon dioxide dissolved in water in the form of bicarbonates to manufacture food.

Question 103.
In the experiment to prove that starch is produced during photosynthesis. Why do we boil the leaf in alcohol?
Answer:
We boil the leaf in alcohol to remove all the chlorophyll present in the leaf. The leaf turns to white in colour.

Question 104.
In the experiment to show that sunlight is necessary for photosynthesis, why do we immerse leaf in boiling water?
Answer:

1. Immersing leaf in boiling water will breakdown the cell membranes of leaf cells.
2. It makes the leaf more permeable to iodine solution, so that it can reach the starch present inside the leaf cells.

Question 105.
Why do we have to destarch the leaf before conducting experiment on photosynthesis?
Answer:
This is because if starch is present it will interfere with the result of the experiment.

Question 106.
Why is a water bath used for heating alcohol in which leaf is kept inside the beaker for testing the presence of starch?
Answer:
A water bath is used here for heating alcohol because alcohol is a highly inflammable liquid. So if alcohol is heated directly over a flame, then it will catch fire at once.

Question 107.
What are the reasons for vomiting?
Answer:
Causes for vomiting :

1. Overeating especially when the food contain a high proportion of fat.
2. When we eat something very indigestible or poisonous.

Question 108.
Why do we feel bilious or liverish?
Answer:
We feel bilious or liverish because of having eaten rich meals for several days.

10th Class Biology 1st Lesson Nutrition 2 Marks Important Questions and Answers

Question 1.
Vitamin A, D, E and K are fat soluble vitamins. Write the deficiency diseases and resources of these vitamins in a tabular form.
Answer:

Vitamin – A	Night blindness, myopia, dry eyes, scaly skin	Leafy vegetables, Carrot, Tomato, Pumpkin, Fish, Egg, Liver, Cod liver oil, Shark liver oil, Milk.
Vitamin – D	Rickets	Liver, Egg, Butter, Morning sun rays.
Vitamin – E	Fertility disorders	Fruits, Vegetables, Sprouts, Meat, Egg, Sunflower oil.
Vitamin – K	Blood clotting do not occur	Green leafy vegetables, Milk

Question 2.
A doctor visited your school to check up the health of school children. What kind of questions do you ask to know about the pancreas?
Answer:

1. Where is pancreas located?
2. Why pancreas is called as mixed gland?
3. What are the hormones released by the pancreas?
4. What are the enzymes released by the pancreas?
5. What are the disorders occur if pancreas does not work properly?
6. What is the role of pancreas in digestion?

Question 3.
Look at the following equation and answer the questions:
Fats + Bile → Fat globules
a) What is the name of that reaction?
b) Which gland plays major role in this reaction?
Answer:
a) The name of the reaction is Emulsification.
b) The gland LIVER plays major role in this reaction.

Question 4.

We know that food is the main source to maintain biological processes in a perfect manner. Our diet should be a balanced one which contains proper amount of carbohydrates, proteins, vitamins, mineral salts and fats. Two third of world population is affected by food related diseases. Some of them are suffering by consuming high calorific food. Most of them are facing various diseases due to lack of balanced diet. Eating of food that does not have one or more than one nutrients in required amount is known as malnutrition. Poor health, will full starvation, lack of awareness of nutritional habits, socio-economic factors are all the reasons of malnutrition.

i) Define Balanced diet.
ii) What is malnutrition and what could be the possible reasons for it?
Answer:
i) The food containing proper amount of carbohydrates, proteins, vitamins, mineral salts and fats is known as “balanced diet”.

ii) Eating of food that does not have one or more than one nutrients in required amounts is known as “malnutrition”.
Poor health, starvation, lack of awareness of nutritional habits, socio-economic factors are all reasons for malnutrition.

Question 5.
What questions do you ask your teacher to know about the obesity and its consequences?
Answer:

1. What are the reasons for Obesity?
2. How to reduce the body weight?
3. What are the consequences of obesity?
4. What type of food you suggest to people suffering from obesity?

Question 6.
Prepare four questions for the Gastro-enterologist to know the problems that occur in the digestive system.
Answer:

1. Why do the people suffer from indigestion problems?
2. Why do we get vomitings?
3. Why do we get belching?
4. Why do we get ulcers in stomach?
5. What is acidity?

Question 7.
Balance the following equation. Write what you have received through this equation.

Answer:

1. This equation represents the process of photosynthesis. For the photosynthesis to occur, four factors are required. They are carbon dioxide, water, light and chlorophyll.
2. 6 molecules of carbon dioxide and 12 molecules of water in the presence of sun light and chlorophyll forms 1 molecule of glucose, 6 molecules of water and 6 molecules of oxygen.

Question 8.
Pregnant ladies are advised to eat leafy vegetables and take folic acid pills. Why?
Answer:

1. Folic acid is the part of the B – a complex family of vitamins.
2. Dark green leafy vegetables are a good source of folic acid.
3. Folic acid is often prescribed for pregnant women because it is essential for the normal development of the brain and spinal cord of the foetus.
4. It also help in protection against birth defects.
5. It also required for the synthesis of nucleic acids DNA and RNA.
   Hence pregnant ladies are advised to eat leafy vegetables and take folic acid pills.

Question 9.
You want to know about intestinal juice from your nearby doctor. Which questions do you ask him?
Answer:

1. Which part of the small intestine secrete intestinal juice?
2. Intestinal juice contains which enzymes?
3. Intestinal juice converts peptids into?
4. Sucrose present in intestinal juice converts sucrose to?
5. Digestion of which nutrient resumes in small intestine?
6. Which digestive juice involved in the complete digestion of food?

Question 10.
Photosynthesis process provides food for all organisms. It mainly takes place by two phases. Light reaction is first phase.
H₂O → H + OH
Above equation in light reaction shows what?
Answer:

1. The first phase of photosynthesis is light reaction. It occurs in grana of the chloroplast.
2. During this phase light-activated chlorophyll molecule splits water molecule into Hydrogen (H⁺) and Hydroxyl ions (OH^–)
3. This reaction is known as photolysis of water which means splitting by light (photo means light, lysis means breaking). This was discovered by Hill. Hence it is also called Hill’s reaction.

Question 11.
Write names of the given sentences.
i) Organelle in which photosynthesis occurs.
Answer:
Chloroplast

ii) Life process in which complex food is converted into simple substances.
Answer:
Digestive system

iii) The part after large intestine in digestive tract.
Answer:
Anus

iv) Deficiency of Vitamin “K” causing disease.
Answer:
Delay in blood clotting.

Question 12.
Write about the nutrition in Amoeba. (OR)
Observe the below given organism and write its name. How nutrition occurs in this organism ?
Answer:

1. The mode of nutrition in Amoeba is holozoic nutrition.
2. Amoeba takes in food using temporary finger like extensions called pseudopodia.
3. These pseudopodia fuse over the food particle forming food vacuole.
4. Inside the food vacuole, complex substances are broken down into simple ones which then diffuse into the cytoplasm.
5. The remaining undigested material is moved to the surface of the cell and thrown out.

Question 13.
Write a short note on heterotrophic nutrition.
Answer:

1. Heterotrophic nutrition is that mode of nutrition in which an organism cannot make its own food from simple inorganic materials like CO₂ and water and depends on other organisms for food.
2. Examples are all animals, most bacteria and fungi.
3. Heterotrophs depend on others for their food requirement.

Question 14.
How is a more serious form of indigestion caused?
Answer:

1. A more serious form of indigestion is caused by stomach and duodenal ulcers.
2. These conditions occur more often in people who may be described as hurried or worried.
3. The ulcers occur more often in busy people who get into the habit of hurrying over meals and rushing from one activity to another without sufficient rest.

Question 15.
What is parasitic nutrition? Write briefly about it.
Answer:

1. Parasitic nutrition is that nutrition in which an organism derives its food from the body of another living organism without killing it.
2. The organism which obtains the food is called a parasite and the organism from whose body food is obtained is called the host.
3. A parasite usually harms the host.
4. The host may be a plant or an animal.
5. Parasitic mode of nutrition is seen in several fungi, bacteria, a few plants like cuscuta and animals like plasmodium.

Question 16.
Write about holozoic mode of nutrition.
(OR)
What is holozoic nutrition?
Answer:

1. Holozoic nutrition means feeding on solid food.
2. Holozoic nutrition is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion.
3. The ingested food is digested and then absorbed into the body cells of the organism.
4. The undigested and unabsorbed part of the food is thrown out of the body of the
   organism by the process of ingestion.
5. The human beings and most of the animals have a holozoic mode of nutritions.

Question 17.
Briefly explain about saprophytic nutrition.
(OR)
What are saprophytes? How does nutrition occur in them?
Answer:

1. Saprophytic nutrition is that nutrition in which an organism obtain its food from dead and decaying plant and animal bodies.
2. Organisms having saprophytic mode of nutrition are called saprophytes.
3. Fungi and bacteria are saprophytes.
4. The saprophytes breakdown the complex organic molecules present in dead and decaying matter and convert them into simple substances outside their body.
5. These simple substances are then absorbed by saprophytes as their food.

Question 18.
What is malnutrition? What are the reasons for it? What are the different types of malnutrition?
Answer:

1. Eating of food that does not have one or more than one nutrients in required amount is known as malnutrition.
2. Reasons for malnutrition: Poor health, will-full starvation, lack of awareness of nutritional habits, socio economic factors are all the reasons for malnutrition.
3. Different types of Malnutrition:
   1. Calorie malnutrition,
   2. Protein malnutrition and
   3. Protein calorie malnutrition.

Question 19.
Write a short note on obesity. (OR)
What are the ill effects of obesity?
Answer:

1. Obesity is due to over eating and excess of energy intake.
2. It is a big health hazard. Obese children when grow, they will be target of many diseases.
3. Obesity children usually suffer from diabetes, cardiovascular, renal, gall bladder problems.
4. Eating junk foods and other food habits lead to obesity.

10th Class Biology 1st Lesson Nutrition 4 Marks Important Questions and Answers

Question 1.
Answer the following questions by observing the diagram showing the experiment:
a) What will you prove by this experiment?
Answer:
By this experiment we will going to prove oxygen is released during photosynthesis.

b) What apparatus do you use in this experiment?
Answer:

1. Beaker
2. Test-tube
3. Funnel
4. Hydrilla Plant
5. Burning splinter.

c) What would be the results if the experiment is done in shadow?
Answer:
If we conduct this experiment in shadow no change in the water level of the Test-tube. No photosynthesis occur. No air bubbles are form.

d) What will you do to obtain result from the experiment?
Answer:
If the burning splinter is kept near the mouth of test tube, burns brightly.

Question 2.
Answer the following questions by observing the diagram showing the experiment.
a) What will you prove by this experiment?
Answer:
Carbon dioxide (CO₂) is necessary for the photosynthesis.

b) What apparatus do you use in this experiment?
Answer:
Wide mouthed bottle, split cork, KOH solution, Iodine, Potted plant.

c) Why do we use KOH solution in this experiment?
Answer:
KOH is used for the absorption of CO₂ in the bottle.

d) Why did we study two leaves in this experiment?
Answer:
We should test two leaves of which one must be having the availability of CO₂ and other must not be having the availability of CO₂ to prove that CO₂ is essential for photosynthesis.

Question 3.
Describe an experiment conducted by Joseph Priestley which revealed the essential role of air in the growth of green plants.
(OR)
What is the role of air in the growth of green plants?
(OR)
Write the experiment of bell jar and pudina plant, performed by Priestley to prove that air plays key role in Photosynthesis.
Answer:

1. Joseph Priestley in 1770 performed a series of experiments that revealed the essential role of air in the growth of green plants.
2. Priestley discovered oxygen in 1774.
3. Priestley observed that a candle burning in a closed space, a bell jar, soon gets extinguished.
4. Similarly, a mouse would soon suffocate in a closed space of the bell jar.
5. He concluded that a burning candle or an animal, both somehow, damage air.
6. But when he placed a mint plant in the same bell jars, he found that the mouse stayed alive and the candle when lighted from outside continued burning in the presence of the mint plant.
7. Priestly hypothesized as plants restore to the air whatever breathing animals and burning candles remove.

Question 4.
B₁, B₂, B₃, A, C, D, E, K are the symbols of vitamins. Classify these vitamins based on solubility and diseases due to vitamins deficiency.

S.No.	Water soluble	Disease due to deficiency	Fat soluble	Disease due to deficiency

Answer:

S.No.	Water soluble	Disease due to deficiency	Fat soluble	Disease due to deficiency
1.	B1	Beri – Beri	A	Eye, skin diseases
2.	B2	Glossitis	D	Rickets
3.	B3	Pellagra	E	Fertility disorders
4.	C	Scurvy	K	Delay in blood clotting

Question 5.
During Photosynthesis, several events occurs in the chloroplast. Explain the light dependent reactions.
(OR)
Write the mechanism of light dependent reactions in Photosynthesis.
Answer:
Light reaction takes place in grana thylakoids of chloroplast.
The following events occurs in the light dependent reaction.
1. Step -1: The chlorophyll on exposure to light energy becomes activated by absorbing photons of light energy.
2. Step – II: The activated energy is used in splitting the water molecule into hydrogen (H⁺) and hydroxyl ion (OH^–). This reaction is known as photolysis or Hill’s reaction.
H₂O → H + OH
3. Step – III : Water (H₂O) and oxygen (O₂) are produced by the OH^– ions through a series of reaction.
4. Step – IV: H⁺ ions are involved in the synthesis of ATP and NADPH which are the end products of light reaction. These are called assimilatory powers.

Question 6.
You might have conducted and experiment in your school laboratory to prove that CO₂ is essential for Photosynthesis. Raju, who is in 9th class, wanted to perform the same experiment. He had some doubts regarding this experiment. Clarify them.
i) Prior to the experiment, the potted plant was kept in a dark room for a week. Why?
Answer:
To destarch the plant.

ii) KOH pellets were kept in the glass jar. Why?
Answer:
To absorb CO₂

iii) Write the apparatus used to perform this experiment.
Answer:
Potted plant, wide mouthed transparent bottle, splitted cork.

iv) What will be the result, if the same experiment is conducted in dark?
Answer:
Photosynthesis does not take place.

Question 7.
Write the differences between light and dark reactions of photosynthesis.
Answer:

Light reaction	Dark reaction
1. It occurs in the grana of the chloroplast.	1. Occurs in the stroma of the chloroplast.
2. It occurs only in the presence of light.	2. It occurs in the presence or absence of light.
3. Light reaction absorbs oxygen and light energy.	3. Dark reaction absorbs only CO2.
4. End products are O2, ATP and NADPH.	4. End product is Glucose.
5. Photolysis of water occurs.	5. Carbon fixation occurs.
g. First stage of photosynthesis.	6. Second stage of photosynthesis.

Question 8.
Draw a neat labelled diagram of internal structure of leaf. Which mesophyll cells of the leaf consist of chloroplast?
Answer:
Palisade parenchyma and spongy parenchyma consist of chloroplast.

Question 9.
Keep a plant for a week in the dark. Then insert one leaf of this plant into a transparent bottle containing potassium hydroxide solution. Keep the plant in sunlight. Test the leaf in the bottle and any other leaf of the plant with Iodine, after a few hours.
i) What is the aim of this experiment?
ii) What will be observed in the leaf kept in the bottle and a leaf from the plant?
iii) Why was the plant kept in the dark first and then in the sunlight?
Answer:
i) To prove that CO₂ is necessary for photosynthesis.
ii) The leaf part kept in the bottle does not show colour change in iodine test, whereas the leaf exposed to air turns bluish-black in the iodine test.
iii) To remove starch from leaves (destarching).

Question 10.
Analyse the following information and answer the questions.

Vitamins	Resources	Deficiency symptoms
Thiamine	Cereals, oil seeds, vegetables, milk, meat, fish, eggs	Vomitings, fits, loss of appetite, difficulty in breathing, paralysis.
Ascorbic acid	Green leafy vegetables, citrus fruits, sprouts, carrot	Delay in healing of wounds, fractures of bones.
Retinol	Leafy vegetables, carrot, tomato, pumpkin, papaya, mango, meat, fish, egg, liver, milk, cod liver oil, Shark liver oil.	Night blindness, xeropthalmia, cornea failure, scaly skin.
Calciferol	Liver, egg, cod liver oil, Shark liver oil	Improper formation of bones, knock-knees, swollen wrists, delayed dentition, weak bones.
Tocoferol	Fruits, vegetables, sprouts, sunflower oil	Sterility in male, abortions in female.
Phylloquinone	Green leafy vegetables, milk, meat, eggs	Delay in blood clotting, over-bleeding.

i) Which vitamins deficiency causes diseases related to bones?
Answer:
Calciferol – Vitamin – D, deficiency causes diseases related to bones,

ii) Which vitamins we get by eating fruits?
Answer:
Retinol – Vitamin – A, and Tocoferol – Vitamin – E we get them by eating fruits,

iii) Which vitamin deficiency causes Paralysis? To prevent iii), what type of food we have to eat?
Answer:
Paralysis is caused by the Vitamin (B}) Thiamine deficiency.
To prevent this disease, we have to eat cereals, oil seeds, vegetables, milk, meat, fish and eggs.

iv) To avoid vitamin deficiency diseases, what type of food we have to eat?
Answer:
To avoid vitamin deficiency diseases, we have to take proper diet.
Our diet should be a balanced one which contains proper amount of carbohydrates, proteins, vitamins, mineral salts and fats.

Question 11.
What are fat soluble vitamins? Explain the deficiency diseases due to deficiency of fat soluble vitamins and their symptoms.
Answer:
Fat soluble vitamins :

Name of the vitamin	Name of the diseases	Symptoms
Vitamin – A (Retinol)	Night blindness, xerophthalmia	Cornea failure, unable to see during night, scaly skin
Vitamin – D (Calciferol)	Rickets	Improper formation of bones, knock- knees, swollen wrists, delayed in dentition, weak bones
Vitamin – E (Tocoferol)	Sterility	Sterility in males, abortions in females
Vitamin – K (Phylloquinone)	Over-bleeding	Delay in blood clotting

Question 12.
Read the table and answer the following questions.

Sl. No.	Vitamin	Resources	Deficiency disease	Symptoms
1.	Cyanoco- balamine	Synthesised by bacteria present in the intestine.	Pernicious anaemia	Lean and weak, less appetite.
2.	Ascorbic acid	Green leafy vegetables, citrus fruits, sprouts	Scurvy	Delay in healing of wounds, fractures of bones.
3.	Retinol	Leafy vegetables, carrot, tomato, pumpkin, papaya, mango, meat, fish, egg, liver, milk, Cod and Shark liver oil	Eye and skin diseases	Night Blindness, Xeropthalmia, Cornea failure, Scaly skin.
4.	Tocoferol	Fruits, vegetables, sprouts, sunflower oil	Fertility disorders	Sterility in males, abortions in females.
5.	Phylloquinone	Green leafy vegetables, meat, egg and milk	Problems related to blood clotting	Delay in blood clotting, over bleeding.

i) Name the anti-sterility vitamin from the above table.
Answer:
Tocoferol (Vitamin E) is the anti – sterility vitamin.

ii) WTiich vitamin deficiency that causes the gums bleeding?
Answer:
Ascorbic acid (Vitamin C) deficiency causes the gums bleeding.

iii) Name the fat soluble vitamins from the above.
Answer:
Retinol (Vitamin A), Tocoferol (Vitamin E), Phylloquinone (Vitamin K) are fat soluble vitamins.

iv) Name the symptoms that appear due to deficiency of vitamin K.
Answer:
Delay in blood clotting, over bleeding are the symptoms appear due to deficiency of vitamin K.

Question 13.
Mention different modes of nutrition. Explain the mode of nutrition in Cuscuta.
Answer:
There are different modes of nutrition
Parasitic Nutrition in Cuscuta :

1. Cuscuta plant is the best example for parasitic nutrition.
2. It contains no chlorophyll and has root like structures called haustoria.
3. With the help of haustoria, cuscuta absorbs nutrients from it’s host plant.
4. As cuscuta grows on the host plants, its roots gradually degenerated and it establishes firmly on the host plant.
5. Meanwhile, the root rots away after stem contact has been made with a host plant.
6. As dodder grows, it sends out new haustoria and establishes itself very firmly on the host plant.
7. After growing in a few spirals around one host shoot, the dodder finds its way to another.
8. It continues to twine and branch until it resembles a fine densley tangled web of thin stems enveloping the host plant.

Question 14.
Is the malnutrition reason for diseases? Why? Write any of such disease and its characters.
Answer:

1. Yes, malnutrition is the reason for occurrance of diseases.
2. Malnutrition is eating of food that does not have one or more than one nutrients in required amount.
3. This results in scarcity of nutrients for the proper growth and health of the individual.
4. Kwashiorkor disease occurs in children due to the deficiency of proteins in the diet.
5. Characteristic features of kwashiorkor disease :
   1. Body parts becomes swollen due to accumulation of water in the intercellular spaces.
   2. Very poor muscle development, swollen legs, fluffy face, difficult to eat, diarrhoea, dry skin are the symptoms of Kwashiorkor disease.
   3. The child becomes lethargic and shows little interest in its surroundings or in playing and learning.

Question 15.
Which issues do you take into consideration to tell that plants play a key role in animals nutrition?
Answer:

1. Plants play a very important role in nutrition of animals. Actually plants are the producers whereas animals are dependent on plants for their nutrition.
2. Many plants or plants parts are eaten as food. There are around 2000 plant species which are cultivated for food. Nutrients like carbohydrates, proteins, fats, vitamins and minerals are available from these plants.
3. Seeds of plants are good sources of food for animals including humans because they contain many healthful fats.
4. Infact majority of the food consumed by human beings are seed based food. Edible seeds include cereals like wheat, rice, maize etc. and legumes like pea, groundnut and nuts.
5. Oil seeds are often pressed to produce rich oils like sunflower, groundnut, sesame etc.
6. Seeds are typically high in unsaturated fats and considered as a health food.
7. Fruits are the ripened ovaries of plants including the seeds within. Many plants and animals have coevolved such that the fruits of the former are an attractive food source to the later.
8. Vegetables are a second type of plant matter that is commonly eaten as food.
9. Hence all the nutrients required by animals are available to the animals from plants. Hence plants are playing an important role in nutrition of animals including human beings.

Question 16.
Give examples for the vitamin deficiency diseases.
Answer:

S. No.	Vitamin	Deficiency diseases
1.	Thiamine (B1)	Beri beri
2.	Riboflavin (B2)	Glossitis
3.	Niacin (B3)	Pellagra
4.	Pyridoxine (B6	Anaemia
5.	Cyanocobalamine (B12)	Pernicious anaemia
6.	Folic acid (B9)	Anaemia
7.	Pantothenic acid	Burning feet
8.	Biotin	Nerves disorders
9.	Ascorbic acid (Vitamin C)	Scurvy
10.	Retinol (Vitamin A)	Night blindness, Xerophthalmia, Rupture of cornea, Scaly skin
11.	Calciferol (Vitamin D)	Rickets, fragile bones
12.	Tocoferol (Vitamin E)	Fertility disorders, Sterility in males, Abortions in females
13.	Phylloquinone (Vitamin K)	Blood clotting

Question 17.
We know that by taking different types of food materials we will get vitamins. For this what changes shall we take in our food habits?
Answer:

1. Eating of rice polished only for one time gives us vitamin thiamine in abundant amount.
2. We should eat balanced food containing nutrients in equal quantities.
3. Fresh leafy vegetables are rich source of vitamins Riboflavin, Folic acid and Vitamin ‘C’. So our diet should contain these leafy vegetables.
4. Sufficient amount of non-vegetarian foods like meat, poultry, fish, kidney and liver should present in our food.
5. Eating fresh fruits also add number of vitamins to our body.
6. Whole cereals like wheat, rice provide number of vitamins to our body. So we shall eat required quantities of cereals in our food.

Question 18.
Describe what disaster occurs on earth, if photosynthesis life process stops.
Answer:

1. Plants are the universal food providers. If they stop photosynthesis all the animals would die due to starvation.
2. Plants release oxygen during photosynthesis. It is essential for survival of all living beings. If photosynthesis does not take place, there would be no oxygen on the earth and no chance of survival of life on this planet.
3. plants utilise CO₂ for photosynthesis. If it does not occur, CO₂ utilisation is stopped and hence increase in the levels of CO₂ This leads to global warming.

Question 19.
Describe the experiment conducted by Jan Baptist Von Helmont and discuss his results in the growth of plant body mass.
(OR)
How is water required for the growth of plant body mass?
Answer:

1. In the year 1648 a Belgian scientist Jan Baptist Von Helmont conducted an experiment that continued for five years.
2. He took a small willow tree and planted it in a large pot of soil.
3. Before he did the experiment he carefully measured the mass of the dry soil and mass of the tree.
4. He covered the soil with a lid so that nothing could fall on to the surface of the soil and add to its mass.
5. There were holes in the lid so that the tree could grow out of the soil and so that air and water could reach the roots.
6. Von Helmont left the tree for five years giving it only rain water to drink.
7. At the end of five years he measured the mass of the tree and the mass of the dry soil for a second time.
8. The results of this experiment are shown below.
   

   Mass (Kg)
   	At start	After five years	Change in mass (Kg)
   Tree	2.27	76.74	74.47
   Drv soil	90.72	90.66	0.06

9. This experiment changed the belief of hundreds of years. This is because Von Helmont arrived at a result that
   a) The substances needed for the growth of a plant do not come from the soil only.
   b) The plant grow because of the water it gets.

Question 20.
Write an account on the mechanism of dark reaction.
(OR)
Write an account on carbon fixation.
(OR)
Briefly explain the Melvin Calvin cycle.
Answer:

1. The reactions of photosynthesis which do not require light energy are called dark reactions. These reactions occur both in presence and absence of light.
2. Dark reactions occur in the stroma of the chloroplast and these were discovered by American scientist Melvin Calvin.
3. In the first reaction carbon dioxide is accepted by Ribulose 1 – 5 biphosphate, a five carbon sugar to form hexose sugar.
4. It is an unstable compound so it breaks down into two molecules of three carbon compounds called phospho glyceric acid (PGA).
5. 
6. Phospho glyceric acid undergoes a series of reactions and is converted to glyceral- dehyde – 3 phosphate. NADPH and ATP produced in light reactions are used up at this stage.
   
7. Two molecules of glyceraldehyde – 3 phosphate combine together to form glucose molecule.
8. In the end glucose is converted into starch.
   Summary reaction :
   

Question 21.
Describe the buccal cavity of human beings.
(OR)
How is food masticated in buccal cavity?
Answer:

1. The cavity or space in the mouth is called oral cavity or buccal cavity.
2. Teeth, tongue and openings of three salivary glands are present in buccal cavity
3. Incisors, canines, premolars and molars are the different types of teeth present in the mouth.
4. Tongue is muscular and pushes the food on to the teeth during mastication. It also helps in swallowing the food into oesophagus.
5. Three pairs of salivary glands present in the buccal cavity are parotid, sub-lingual and sub-maxillary glands.
6. Parotid glands are present near the ears. The other two pairs of glands open below the tongue through ducts.

Question 22.
What is indigestion? How can we avoid indigestion?
Answer:
Indigestion: Indigestion is a general term when there is difficulty in digesting food. Healthy people can usually avoid problems related to indigestion by:

1. Having simple, well balanced meals.
2. Eating them in a leisurely manner. ,
3. Thoroughly masticating the food.
4. Avoiding taking violent excercises soon after eating food.
5. Drinking plenty of water and having regular bowel movements.

Question 23.
What are vitamins? Why they are called essential nutrients? What is their role in the human body?
Answer:

1. Vitamins are organic substances.
2. They are micro – nutrients required in small quantities.
3. Actually vitamins are not synthesised in the body and therefore they are essential nutrients.
4. Though our body cannot synthesis vitamins we do not generally suffer from vitamin deficiency disease.
5. This is because of two sources of vitamins for our body. Diet is the primary source.
6. In addition, bacteria present in the intestine synthesis vitamins and supply them to us
7. By themselves vitamins cannot generate any energy or carryout any chemical reaction.
8. In the body vitamins combine with some of the enzymes and make the enzymes active.
9. In the absence of vitamins, enzymes become inactive and cannot catalyse the reactions.
10. Vitamins are normally present in all types of natural foods – milk, meat, fruits and vegetables.
11. Vitamins are of two types:
    1. Water soluble vitamins eg: B complex and Vitamin C and
    2. Fat soluble vitamins eg: A, D, E and K.

Question 24.
Give an account of water soluble vitamins, their occurrence, deficiency diseases and symptoms.
Answer:
Vitamins, available sources and deficiency diseases:

Vitamin	Resources	Deficiency diseases	Symptoms
B complex Vitamins: 1) Thiamine (B1)	Cereals, oil seeds, vegetables, milk, meat, fish, eggs.	Beri Beri	Vomitings, fits, loss of appetite, difficulty in breathing, paralvsis.
2) Riboflavin (B2)	Milk, eggs, liver, kidney, green leafy vegetables.	Glossitis	Mouth cracks at corners, red and sore tongue, photophobia, scaly skin.
3) Niacin (B3)	Kidney, liver, meat, egg, fish, oil seeds.	Pellagra	Dermatitis, diarrhoea, loss of memory scalv skin.
4) Pyridoxine (B6)	Cereals, oil seeds, vegetables, milk, meat, fish, eggs, liver.	Anaemia	Hyper irritability, nausea, vomiting, fits.
5) Cyano cobalamine (B12)	Synthesised by bacteria present in the intestine.	Pernicious anaemia	Lean and weak, less appetite.
6) Folic acid	Liver, meat, eggs, milk, fruits, cereals, leafy vegetables.	Anaemia	Diarrhoea, loss of leucocytes, problems related to mucus in the intestines.
7) Pantothenic acid	Sweet potatoes, ground nuts, vegetables, liver, kidney, egg.	Burning feet	Walking problems, sprain.
8) Biotin	Pulses, nuts, vegetables, liver, milk, kidney.	Nerves disorders	Fatigue, mental depression, muscle pains.
9) Vitamin ‘C’ (Ascorbic acid)	Green leafy vegetables, citrus fruits, sprouts.	Scurvy	Delay in healing of wounds, fractures of bones.

Question 25.
a) What apparatus do you use during the conduction of the experiment?
b) Before conducting the experiment, why do you keep the potted plant in dark place for a week?
c) What test do you conduct to know the formation of carbohydrates in leaves?
d) During the test, which part of the leaf turns into blue and which part doesn’t? Why?
Answer:
a) Potted plant, Light screen, Iodine solution, Petridish, Black paper.
b) To destarch the leaves.
c) Iodine Test
d) The part of the leaf exposed to light turn into blue. Unexposed part does not turn into blue.
Reason: Photosynthesis occurs only in the presence of sunlight. The unexposed part does not receive the sunlight.

Question 26.
Draw the diagram of equipment arrangement in Hydrilla experiment. You did to prove that oxygen releases in photosynthesis. Write the reasons why test tube is placed upside down on funnel.
Answer:
Reasons for placing the test tube upside down on funnel:

1. To count the number of bubbles coming out of the hydrilla twigs per minute during photosynthesis.
2. To collect sufficient amount of oxygen at the end of the test tube so that it can be tested with glowing splinter.
3. Amount of oxygen produced in the test tube can be measured by the displacement of water within the test tube.

Question 27.
Describe the internal structure of the leaf.
(OR)
How is the internal structure of leaf modified to prepare starch through the process of photosynthesis?
Answer:

1. A transverse section of a typical leaf shows that it is covered on both sides by epidermis. Epidermal layers are covered on both sides by cuticle.
2. Lower epidermis is interrupted by a large number of openings called stomata. The central opening is called stoma.
   
3. Each stoma is surrounded by two kidney shaped cells called Guard cells.
4. Stomata regulate the exchange of gases and loss of water vapour from the leaves.
5. Mesophyll is the tissue present between two epidermal layers. Upper mesophyll tissue is called palisade parenchyma and lower tissue is known as spongy parenchyma.
6. The cells in the palisade parenchyma are long elongated arranged in rows.
7. The cells in the spongy parenchyma are irregularly arranged cells with large inter cellular spaces.
8. More number of chloroplasts are present in palisade parenchyma than the spongy parenchyma.
9. In the midrib and veins vascular bundles are present with phloem located towards the lower side and xylem towards the upper side.

Question 28.
Write about the parasitic nutrition in cuscuta plant.
Answer:

1. Dodder (genus cuscuta) is a leafless, twining, parasitic plant belongs to family convolvulaceae.
2. The dodder contains no chlorophyll and instead absorbs food through haustoria.
   
3. The dodder’s seed germinates, forming an anchoring root, and then sends up a slender stem that grows in a spiral fashion until it reaches a host plant.
4. It then twines around the stem of the host plant and throws out haustoria, which penetrate it.
5. Water is drawn through the haustoria from the host plant’s stem and xylem, and nutrients are drawn from its phloem.
6. Meanwhile, the root rots away after stem contact has been made with a host plant.
7. As the dodder grows, it sends out new haustoria and establishes itself very firmly on the host plant.
8. After growing in a few spirals around one host shoot, the dodder finds its way to another and it continues to twine and branch until it resembles a fine densley tangled web of thin stems enveloping the host plant.

Question 29.
Describe the digestion of food materials in alimentary canal with the help of a diagram.
(OR)
How is the food digested in your body?
Answer:

1. The alimentary canal is basically a long tube extending from the mouth to the anus.
2. Food is masticated by our teeth in the mouth and mixed with saliva to make it slippery and wet.
3. Saliva which contains amylase helps in the breakdown of carbohydrates into simple ones.
   
4. The soft food mixed with saliva passes through oesophagus or food pipe by wave like movements called peristaltic movements to the stomach.
5. The gastric glands in the stomach secrete gastric juice that contains hydrochloric acid, protein digesting enzyme pepsin and mucus.
6. Partially digested food chyme is released in small amounts by sphincter muscles reach small intestine.
7. Bile juice secreted by liver and pancreatic juice secreted by the pancreas release into the duodenum of small intestine.
8. Emulsification of fats is done by bile juice. Pancreatic juice contains enzyme trypsin for carrying on the process of digestion of proteins and lipase for fats.
9. Complete digestion of carbohydrates, fats and proteins takes place in the small intestine by intestinal juice.
10. Finger-like projections present in the walls of small intestine are called villi. They absorb the digested food into the blood.
11. Rest of the food is sent into the large intestine where most of the water present in it is absorbed from the food.
12. This material is then expelled through the anus which is the last part of the alimentary canal.

Question 30.
Draw a flow chart of human digestive system.
Answer:

Question 31.
Write briefly about nutrition in paramoecium. (OR)
Explain the nutrition process in paramoecium with the help of diagrams.
Answer:
Paramoecium :

1. Paramoecium is a unicellular aquatic organism.
2. The paramoecium has thin, hair like cilia all over its body.
   
3. The cilia move back and forth rapidly in water.
4. When the cilia is present around, the mouth region of paramoecium move, back and forth. They sweep the food particles present in water into the mouth of paramoecium.
   
5. This is the first step in the nutrition of paramoecium which is called ingestion and is followed by digestion, absorption, assimilation and egestion.

Question 32.
Describe the digestion of food in the stomach. (OR)
How is the food digested in your stomach ?
Answer:

1. The stomach is a large organ which expands when food enters it.
2. The muscular walls of the stomach help in mixing the food thoroughly with more digestive juices.
   
3. The gastric glands present in the wall of the stomach secrete gastric juice which contains hydrochloric acid, pepsin and mucus.
4. The hydrochloric acid facilitates the action of the enzyme pepsin and also kills the germs present in the food.
5. The enzyme pepsin digests proteins and mucus protects the inner lining of the stomach from the action of the acid under normal conditions.

Question 33.
Describe the digestion of food in the small intestine. (OR)
What are the changes that you see during the digestion of food in small intenstine?
(OR)
Small intestine is a long coiled tube. How the food is digested in small intestine of human being?
Answer:

1. The small intestine is the longest part of the alimentary canal.
2. It is the site of the complete digestion of carbohydrates, proteins and fats.
   
3. It receives the secretion of liver and pancreas for this purpose.
4. These juices make the internal condition of the intestine gradually to a basic or alkaline one.
5. Bile juice secreted by liver breaks down fats into small globules like forms. This process is called emulsification.
6. Pancreatic juice contains enzymes like trypsin for carrying on the process of digestion of proteins and lipase for fats.
7. Walls of the small intestine secrete intestinal juice. This is also known as succus entericus.
8. The intestinal juice consists of enzymes like enterokinase, peptidase, lipase, sucrase, nucleotidase, nucleosidase etc.
9. Enzymes present in the intestine completely digest the partially digested food.
10. Following digestive processes take place in the intestine.
    a) Peptidases convert peptides into amino adds.
    b) Intestinal lipase completely digest fats into fatty acids and glycerol.
    c) Enzymes sucrase, maltase, lactase hydrolyse sucrose, maltose and lactose respectively converting them into glucose.
    d) Nucleotidase and nucleosidase complete the digestion of nucleic acids.
11. The end products of digestion are absorbed in the intestine.

Question 34.
What are the health aspects of the alimentary canal?
Answer:

1. The human alimentary canal usually functions remarkably well considering how badly we treat it on occasions.
2. Vomiting is the body’s method of ridding itself unwanted or harmful substances from the stomach.
3. There are many causes of vomiting, but one of the most common is over eating, especially when the food contains a high proportion of fat.
   
4. The liver is unable to cope with the excessive fat and we get a feeling of nausea and sometime headache.
5. Indigestion is a general term used when there is difficulty in digesting food.
6. A more serious form of indigestion is caused by stomach and duodenal ulcers. These conditions occur more often in people who may be described as hurried or worried.
7. Those who are able to relax, who are not continually tensed up, and who live at a slower pace, seldom get ulcers.
8. For good health it is necessary to empty the bowels regularly.
9. If the food residues remain in the colon for too long, the bacteria present have more time to produce harmful substances which may be absorbed by the blood.
10. Constipation can often be avoided by having plenty of roughage in the diet.

 

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 10 Natural Resources Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 10th Lesson Natural Resources

10th Class Biology 10th Lesson Natural Resources Textbook Questions and Answers

Improve your learning

Question 1.
The BP Statistical Review of World Energy in June measured total global oil at 188.8 million tonnes, from proved oil resources at the end of 2010. This is only enough for oil to last for the next 46.2 years. What measures should be taken to conserve oil? What will happen if we do not conserve it?
Answer:
Measures to be taken to conserve oil are:

1. Walk, ride a bike, carpool and use public transportation whenever possible.
2. Prefer public transport system like bus or train instead of travelling in personal vehicles.
3. Choose materials other than plastic which uses crude oil for household items.
4. Use cloth or paper bags instead of plastic bags when shopping.
5. Use organic fertilizers for agriculture and gardening because fossil fuels are used in making chemical fertilizers.
6. Produce renewable biofuels to power cars and trucks.
7. Vehicle owners should keep their vehicles serviced i.e., correct amount of air in fires, oil change, spark plug/fuel injector checks, often-at least quarterly.
8. Drive in the correct gear. Incorrect gear shifting can lead to as much as 20% increase in fuel consumption.
9. Consider a hybrid vehicle or an electric vehicle.

If we do not conserve oil, we never get oil after 46-47 years. So all the industries that depend on the oil for energy will break down. Facilities linked with oil will be hampered. So the future generations will suffer.

Question 2.
Here is a news strip, read it carefully and answer the following questions.

Villagers oppose sand mining project Santhabommali (Srikakulam):

People of more than 20 villages in two mandals of Srikakulam have raised a banner of revolt against the proposed beach sand mining project by o private company and threatened to intensify their agitation if the government does not cancel the project. The sand mining is being taken up to extract rich minerals from the area. The villages are located around the forest belt were mining was initiated.

i) Do you think the villagers are doing the right thing to agitate? Why?
Answer:
Yes, the villagers are doing a right thing to agitate. Because beach sand mining leads to certain problems such as –

1. Destruction of natural beaches and ecosystems.
2. Habitat loss for globally important species such as turtles, shore birds, etc.
3. Destruction of nearshore marine ecosystems.
4. Increased shoreline erosion rates.
5. Reduced protection from storms, tsunamis and wave events.
6. Economic losses through tourist abandonment.
7. Loss of coastal aesthetics and
8. Increased saline water intrusion.

The threats posed by sand mining are made even more critical given the prospect of a significant rise in global sea level over the coming decades,

ii) What resources are the villagers trying to save by their agitation?
Answer:

1. Villagers can save the biodiversity of the area by agitating.
2. They can save flora like mangroves and fauna like turtles, gharials (a species of crocodiles) etc.

iii) Will the villagers be benefited by the rich minerals extracted from sand?
Answer:

1. No, the villagers will not be benefitted by the rich minerals extracted from sand.
2. Extraction of minerals may provide employment for few people in that area but most of the local people who are depending on fishing for their livelihood may lose their livelihood as the sand mining brings some disturbances in the ecosystem.

iv) Why does the private company want to carry out mining in the area?
Answer:
Private company wants to carry out mining in that area, for the rich minerals like Titanium and Zirconium. That can be extracted from the sand in the beaches.

v) Does the government have any role to play?
Answer:

1. The government’s role is very important in this regard.
2. It has to make some laws to protect the beaches and their biodiversity.
3. These laws should be implemented very carefully.
4. Indiscriminate and unlawful mining should be prohibited strictly.

vi) How will mining in that piece of land affect people of the area?
Answer:
Mining in that piece of land affects people of the area in many ways.

1. People who depend on tourism may lose their livelihood.
2. People who depend on fishing and other natural products may also lose their livelihood.
3. They may not get proper drinking water due to increased saline water intrusion
4. They may get severe loss whenever natural calamities like tsunamis and storms occur due to reduced protection.
5. In severe cases they have to leave that place due to increased soil erosion and deepening of seashore.

Question 3.
What is sustainable development? How is it useful in natural resource management?
Answer:
Sustainable development: When we use the environment in ways that ensure we have resources for the future, it is called sustainable development.
Useful in natural resources management:

1. Sustainable development ensures the judicial management of natural resources.
2. It helps in optimum utilization of alternative resources and renewable resources.
3. Thus it helps in decreasing the ever increasing demand for fossil fuels and non-renewable resources.
4. Sustainable development practices will give more scope for planning new methods of natural resource management.

Question 4.
Write a detailed note on management of a natural resource.
Answer:

1. Natural resource management refers to the management of natural resources such as land, water, soil, plants and animals, with a particular focus on how management affects the quality of life for both present and future generations.
2. The main goal of natural resource management is sustainability – balancing social, economic and environmental factors to make sure that our children and grandchildren can equally benefit from our natural resources.
3. Our social, economic and environmental well-being depends on the sustainable management of natural resources.
4. Natural resource management deals with managing the way in which people and natural landscapes interact.
5. It brings together land use planning, water management, biodiversity conservation and the future sustainability of industries like agriculture, mining, tourism, fisheries and forestry.
6. Natural resource management specifically focuses on a scientific and technical understanding of resources and ecology and the life-supporting capacity of those resources.
7. The various approaches applied to natural resource management include
   a) Command and control
   b) Community-based natural resource management
   c) Adaptive management
   d) Precautionary approach and
   e) Integrated natural resource management
8. Reduce, Reuse and Recycle are the key concepts for Natural resource management.

Question 5.
Suggest some ways of reusing a resource in your locality.
Answer:
Reusing of a resource (water) in our locality :

1. Washing hands in the garden.
2. Washing machine rinse water can be used for toilet flushing and floor cleaning.
3. Water from washing of fruits and vegetables can be used to water plants.
4. Laundry water can be reused to clean the cars.
5. Even the drain water can also be recycled.
6. After purification recycled water can be used for agriculture.
7. Recycled water can be used to cool down the machinery in the industries.
8. Once used water can be used to recharge the ground water.
   Once used water can be used again like this to conserve the water resource.

Question 6.
Why should we conserve forests and wildlife?
Answer:
We should conserve forests and wildlife for the following reasons.

1. These are the rich habitat for plants and animals (wildlife).
2. Forests are needed for the smooth functioning of biogeochemical cycles.
3. Forests are necessary for the formation of humus and for maintaining soil fertility.
4. Forests serve as lung for the world. They purify air and protect the earth from greenhouse effect and global warming.
5. Many industries such as sport equipment, paper, lac manufacturing, timber and furniture etc., depend on forests.
6. Forests and wildlife provide many fruits, medicines, dyes, sandal wood, bamboo, etc.
7. Forests provide employment to a large number of people and also help in generating revenue.
8. Wildlife act as ‘gene bank’.
9. Conservation of wildlife ensuring that all diverse species in an area survive, breed and flourish.
10. Conservation of forests and wildlife is vital for the ecological stability of a particular area.

Question 7.
Suggest some approaches towards the conservation of forests.
Answer:
The approaches towards the conservation of forests.

1. Sustainable forestry methods should be adapted.
2. Avoiding certain logging techniques such as removing all the high-value trees or all the largest trees from a forest should be avoided.
3. There should be proper laws for the exploitation of forest resources.
4. People should be made more aware about the importance of forests.
5. All possible forest should be announced as the reserve forests.
6. Participation of local people and villagers must be taken in the conservation of forests and they should be given proper employment.
7. Over exploitation by industrial groups and due to the activities of tourist depart¬ment should be checked.
8. There should be incentives and rewards for the efforts made by the people towards the conservation of forests.
9. Overgrazing of forest vegetation by the cattle of local people should be prevented.
10. Measures should be taken to prevent and control forest fires.

Question 8.
Natural resources are decreased more rapidly. Guess what will be the consequences.
What are the consequences of depletion of natural resources?
Answer:
The consequences of rapid decrease of Natural resources.

1. The resources scarcity will arise shortly and demand for them will increase.
2. Future generations may not get these resources.
3. Vehicles running with fossil fuels become useless.
4. All the industries that depend on these sources will shutdown.
5. Electricity production through these sources will be stopped. So we have to stay in dark during night.
6. All the utensils and other articles should be made out of recycled materials.
7. Balance in the nature will be disturbed due to decrease in these sources like forest and biodiversity.
8. We have to search for other sources as the alternative for these resources.

Question 9.
Prepare a questionnaire to conduct interview with petrol filling station personnel about consumption of fossil fuels. (OR)
What questions are you going to ask petrol-filling personnel about consumption of fossil fuels?
Answer:
Questionnaire to conduct interview with petrol filling station personnel about the consumption of fossil fuels:

1. What is the name of the filling station?
2. Where is it located (landmark)?
3. How many litres of petrol is being imported everyday or week or month?
4. How many litres of diesel is being imported?
5. How many two wheelers are being filled everyday here?
6. How many autos are being filled everyday here?
7. How many lour wheelers are being filled everyday here?
8. How many litres of petrol is being sold per day in this filling station?
9. How many litres of diesel is being sold per day in this filling station?
10. What is the total amount of fossil fuel consumed by the people through this filling station per month?
11. Why the rates of petrol and diesel changing everyday?

Question 10.
Prepare model for rain water harvesting or energy saving or soil management. That reflect your innovative thoughts.
Answer:
Rain Water Harvesting:
Procedure to prepare a model for rain water harvesting:

1. Make a model of a house with roof little slanting towards one side.
2. Connect a tube/pipe to the down end such that the rain water that falls on roof can be collected.
   
3. Connect the other end of this tube to a barrel like structure which can be used as storage tank.
4. From the tank arrange a tube towards the garden along with a valve that can be closed and opened.
5. Arrange one more tube with valve into a recharge pit or percolation pit arranged at one corner.
6. Arrange a tap to the tank that can be opened to collect the water for cleaning floor, vehicles etc.
7. During rain, water from roof can be collected into tank and we can utilize it later for gardening or cleaning purposes.
8. When water is in excess it can be used to recharge underground water.

Question 11.
List out names of villages, farmers and procedure followed to the restoration of any natural resource in your area.
(OR)
How villagers and farmers of your village restore natural resources in your area?
Answer:

S.No.	Village name	Farmer’s name	Procedure followed to restoration of natural resources
1.	Kandlagunta	Ch. Ramaiah	Constructed recharge pits to restore under – ground water.
2.	Kotappakonda	B.Bangar Raju	Constructed check dams to restore under – ground water.
3.	Reddy Palem	T. Ranganadh	Recharged the well by building dykes in the nalla.
4.	Uppalapadu	R. Sundaram	Motivated the villagers to construct percola­tion pits.
5.	Nagaram Palem	D. Raja Reddy	Removed silt from the tank.

Question 12.
You might have heard the Natural Gas drillings near Kakinada by ONGC (Oil and Natural Gas Corporation). Collect information and prepare a note on the status of Gas production at the basin.
Answer:

1. Presently ONGC producing gas at the rate of 3.05 MMM³ / day to 4.0 MMM³ / day.
2. ONGC, GSPC, Reliance Industries are companies exploring oil and natural gas in this region.
3. GAIL is marketing and distributing the natural gas through gas collection station.
4. ONGC is associated with GAIL, in planning the additional facilities and technical inputs needed for the future enhanced gas supplies.
5. ONGC has established mini oil refinery at Tatipaka.
6. Total allocation of natural gas from K.G. area is 8.5 MMM³ / day.
7. ONGC has already projected a production potential of 6.5 MMM³ / day of availability of which entire quantity has been allocated to the industrial consume of the area.
8. 16 Industries are actively using Natural gas investing Rs. 5500 crores are working well for power generation, steel re-rolling, producing fertilizers, etc. and some power projections are almost invested Rs. 4000 crores and waiting for a supply of Natural gas.

Question 13.
Does your village or nearest city have a mechanism in place for recycling these waste materials? Find out how it is done and write in detail.
Answer:
Near to our village, there is a center that recycles paper waste. Here the waste paper is recycled in the following way.

1. Waste paper is collected from various sources.
2. This paper is taken to the recycling plant where it is separated into types and grades.
3. The separated paper is then washed with soapy water to remove inks, plastic film, staples and glue.
4. The paper is put into a large holder where it is mixed with water to create slurry.
5. By adding different materials to the slurry different paper products can be created, such as cardboard, newsprints or office paper.
6. The slurry is spread using large rollers into large thin sheets.
7. The paper is left to dry.
8. Then it is rolled up, ready to be cut and sent to the shops.

(OR)

Plastic Recycling process:
Stage – 1: Plastic needs to collected by the recycling company. Once plastic arise recycling plant, the first stage is to sort the plastic into specific types because plastic recycling is more complex than of other metals like glass or paper. Due to many different types of plastic, mixed plastic cannot be used in manufacturing without delivering poor quality products.

Stage – 2: Once the waste plastic is identified and separated, the cleaning process will begin. This starts with washing to remove paper labels, adhesives and other impurities to be completely removed as this lowers the quality of recyclic plastic.

Stage – 3: The shredding stage is when the plastic is taken and loaded on to conveyor belts or directly into huge hoppers, that funnel the clean scrap towards rotating metal teeth that rip the plastic into small pellets which are bagged up and ready for testing.

Stage – 4: Identify and classify the plastic: Once the shredded plastic has been bagged, it is then chemically tested and labelled as to it’s exact specification. This grade plastic can be used as it is by adding to a mix of vergin plastic in a manufacturing run alternatively the grade plastic can be further recycled.

Stage – 5: Extruding: This is the final stage in recyclic plastic. This involves cleaning and melting, shredded plastic and extruding the form of pellets which then go on to manufacture the next lot of plastic products.

Reasons to recyclic plastic:
Millions of tons of waste plastic end up in land fill. When the vast majority of it can be recycled, it is too easy to throw away rubbish without second thought.

But we need to take care of our planet and not just reducing the amount of rubbish we bury but also given that plastic is derived from oil, a natural product with ever depleting resource, it makes sense to recycling as much as possible.

Question 14.
Collect any graph that shows oil (petroleum) consumption in India.
i) Does the production meet consumption in India?
ii) During which period of time shows highest increase in consumption rate?
iii) What will you say happened to production from past ten years, for example, 2004 to 2014?
iv) Suggest some ways to bring down the consumption of petroleum.
Answer:
i) No, the production of oil doesn’t meet the consumption in India.
ii) During 2009 to 2011, there is highest increase in consumption rate.
iii) There was a gradual increase in production from 2001 to 2011. 139.94 million bbl more petroleum was produced in 2011 than 2001. But it does not meet the increased consumption. 1242.27 million bbl more petroleum was consumed in 2011 than 2001. This is nearly nine times more than growth in production.
iv)

1. Using public transport.
2. Walking, using car pool whenever possible.
3. Using hybrid vehicles/electric bikes.
4. Planning alternate source of energy like biofuel.
5. Using products free from petrochemicals like organic fertilizers instead of chemical fertilizer, cloth or paper bags instead of plastic bags etc., can bring down consumption of petroleum.

Question 15.
Proper utilization of natural resources is the way to show gratitude to our nation. Can you support this statement? Give your argument.
Answer:
Yes, I support this statement for the following reasons.

1. Natural resources are our natural wealth which is very essential for our well-being and economic growth.
2. The growth and development of any nation depend on its natural resources and their proper utilisation.
3. We are enjoying the fruits of these resources which is provided by our nation to us.
4. In return, it is our responsibility to safeguard our nation’s wealth.
5. For this it is very essential to utilise these natural resources in such a way that they will remain in our nation and available for the future generations.
6. If we don’t utilize them in proper way there will be crisis for these resources and we have to depend on other nations for it.
7. Such a situation will damage our economy and life standard, for which we are the responsible persons.
8. So, proper utilisation of natural resources is surely the way to show gratitude to
   our nation.

Question 16.
Crop selection and cultivation should be based on the availability of water. Prepare a slogan to make aware of farmers about this.
Answer:

1. See the water availability – Choose the crop.
2. Use micro irrigation – Save water for future.
3. Use less water – Get more productivity.
4. Need based irrigation – Best production.
5. Less water availability – Use dry land crops.
6. Drop by Drop – Grow and grow.
7. Sprinkle water on crop – Crop feels happy.
8. See the water – Grow the crop.
9. Today’s rain water to tomorrow’s life saver.
10. No matter your occupation – Water conservation is your obligation.

Fill in the blanks.

1. ———– plants are used for production of biofuels.
2. Biodiversity is important for more than just food and for ———– also.
3. Example for non-renewable resource is ———–
4. ———– is the alternative method to prevent groundwater depletion.
5. Cultivation of paddy is suitable for ———– areas.

Answer:

1. Jatropha curcas
2. medicines
3. coal, petroleum
4. Water storage structure
5. water rich

Choose the correct answer.

1. Percolation tanks helps to  [ ]
   A) Supply water for agriculture
   B) Increase ground water level
   C) Preserve rain water
   D) Prevent overflow water from tanks during rainy season
   Answer: B/C
2. Which of the following practices is suitable to farmer at less water resources?  [ ]
   i) select short term crops
   ii) cultivate commercial crops
   iii) adapt drip system
   iv) crop holiday
   A) i, iii
   B) i, ii, iii
   C) i, iv
   D) iii, iv
   Answer: B
3. Which of the fossil fuel reserves decrease more rapidly in India?  [ ]
   A) natural gas
   B) coal
   C) petroleum
   D) all
   Answer: C
4. Huge amount of toxic chemicals leak into the surrounding ecosystem because of  [ ]
   A) industries
   B) mining
   C) pesticides
   D) modern technology
   Answer: B
5. Sustainable development means  [ ]
   A) prevention of wastage
   B) stable growth
   C) development without damaging
   D) high yielding in less time
   Answer: C

10th Class Biology 10th Lesson Natural Resources InText Questions and Answers

Table-1: Area under irrigation

Village	Total Area (acres)	Percentage Area Irrigated	Number of Wells	Sample Size
Village -1	3791	25%	155	25
Village – 2	2970	15%	175	25

Question 1.
a) What is the total irrigated area in acres, in Village – 1?
Answer:
The total irrigated area in Village -1 is 947.75 acres.

b) If one needs to irrigate all the land in Village -1 how many wells would be required?
Answer:
Number of wells required to irrigate all the land in Village -1 are 620.

c) Though the number of wells is less in Village -1, the area under irrigation is more as compared to Village – 2. How is this possible?
Answer:
The area under irrigation is more in Village -1 when compared to Village – 2 because the farmers in Village – 1 use water resource jointly and follow micro irrigation techniques.

d) Do you think the area under irrigation will change due to rise in population?
Answer:
No, the area under irrigation will not change due to rise in population.

Table 2: Status after five years

Village	Percentage Change in area under irrigation	Percentage decline in number of wells	Percentage change in area under crops
			Paddy		Cotton	Gingelly	All crops
			K	R			K	R
Village -1	-14	-39	-17	-17	163	86	11	-17
Village – 2	-30	-68	-22	-50	27	138	-05	-50

K stands for Kharif while R stands for Rabi. Negative values indicate loss/ decline, while positive ones show gain/rise.
Question 2.
a) If the number of wells is 155 now, what was it 5 years back ?
Answer:
5 years back nearly 215 wells were there.

b) What do you think ‘decline in number of wells’ represents?
Answer:
Decline in number of wells represents fall of ground water levels due to less rainfall.

c) How would crops be affected due to decline in the number of wells?
Answer:
The crops do not grow well and the yield is less due to decline in the number of wells.

d) Compare table 1 and 2 and state what they tell us about the area under irrigation in both the villages?
Answer:
When compared table 1 and 2 the area under irrigation in Table – 2 is decreased.

e) Which village do you think is more affected?
Answer:
Village – 2 is more affected.
f) What is the change in types of crops grown in the villages?
The crops which need less water and has less duration are grown.

Question 3.
If 45 per cent of wells have dried up in Village -1 and there is 39 per cent decline in number of wells, what percentage of wells do you think have been converted to bore wells?
Answer:
84% of wells have been.converted to bore wells.

Question 4.
By comparing the two villages, find out where greater number of wells dried up? What methods would have saved the wells in other village?
Answer:
By comparing the two villages Village – 2 has greater number of wells dried up. Percolation tank in Village -1 saved the wells drying up.

Question 5.
Which type of farmers, those having small land holdings or those with large land holdings are most affected when wells dry up?
Answer:
The farmers having large land holdings are most affected.

Question 6.
If water resource becomes scarce, will it affect the nature of soil in an area?
Answer:
Yes, it will also affect the nature of the soil in an area.

Question 7.
As wells dry up, how are people in the area dependent on the well affected?
Answer:
Open wells have dried up, water tables have gone down.

Question 8.
Why do you think water became scarce mainly in Village – 2?
Answer:
Water is pumped out of wells and bore wells using electricity leads to water scarcity.

Question 9.
Table 3 : Annual expenditure on well irrigation for small and large farmers(2002)

a) Is the availability of water resource same for a small and a large farmer?
Answer:
Yes the availability of water resource is same for a small and a large farmer.

b) Do you think the availability should be same for everyone in an area?
Answer:
Availability should be the same as the ground water level is same in all places.

c) A well irrigates more area in Kharif season as compared to Rabi, how is it possible?
Answer:
A well irrigates more area in Kharif season as compared to Rabi because Kharif occurs in rainy season and Rabi in winter season. So well irrigation is more in Kharif season.

d) How should a farmer utilize such a condition?
Answer:
Farmer wants to irrigate more land in Kharif season to grow more crop to get more yield.

e) If a well can irrigate 2.5 per cent of cultivable land, how many wells would irrigate whole of the land?
Answer:
The number of wells required to irrigate whole land in Village -1 are around 1516 wells.

f) Which factor has a greater effect on expenditure, number of wells or depth of a well?
Answer:
Depth of a well has greater effect on expenditure.

g) What is the total expenditure on a whole cultivable land owned by a small farmer in Village – 2? How do you think a small farmer meets this expenditure?
Answer:
The total expenditure on a whole cultivable land owned by a small farmer in Village – 2 is around 20,000 – 45,000 rupees per acre per year. The small farmer meets this expenditure through agricultural loans from banks.

h) What could help the small farmer reduce expenditure?
(Hint: Think of crops that require less water)
Answer:
Cultivating the crops which require less amount of water.

i) Do you think increasing the depth of bore well is a good solution for increasing total land area under irrigation? Why/Why not?
Answer:
Increasing the depth of bore well is not a good solution for increasing total land area under irrigation. This is because with increasing depth, expenditure also will increase so net profit will decrease. Moreover, groundwater level decreases much more and has to dig more depth.

Question 10.
Table 4: Income on crops

Village	Type of Farmer	Net income per acre in Rupees				Total income per acre year in rupees
		Paddy Kharif	Paddy Rabi	Cotton	Gingelly
Village -1	Large	8200	8700	4900	3300	25100
	Small	7046	8490	10889	3110	29535
Village – 2	Large	10698	5970	4000	3595	24263
	Small	9128	7380	3031	2650	22189

a) Which crop is most profitable for a small farmer in Village – 2?
Answer:
For a small farmer in Village – 2 paddy in Kharif Is more profitable.

b) What is the difference between a small farmer in Village – 1 and Village – 2?
Answer:
Small farmer in village -1 is getting more income than farmer in Village – 2.

c) Which crop could replace paddy and the profitable as well for a small farmer in Village – 1?
Answer:
Cotton crop could replaces paddy, it is more profitable than others.

d) Though we know that paddy consumes maximum water, why do you think farmere still like to grow paddy?
Answer:
Though paddy consumes maximum water, farmers believe that it is profitable and less risky. It Is a staple food for people. So they still like to grow paddy.

e) What is the impact of a depleting resource upon the farmers?
Depleting resource increases the cost of production. So the farmers are becoming poor and poor as cost increases and profit or income decreases.

f) Do you think the income of a small farmer in Village – 2 is sufficient enough to meet his expenditure?
Answer:
No, the income of a small farmer in Village – 2 is not sufficient enough to meet his expenditure.

g) What are the major causes of pitiable condition of small farmers at Village – 2?
Answer:
The major causes of pitiable condition of small farmers at Village – 2 are

1. Lack of awareness regarding sustainable use of natural resources like water.
2. Not adopting crops suitable to their conditions.

h) Do you think farming as an occupation is profitable for the small farmer in Village – 2?
Answer:
No. Farming as an occupation is not profitable for the small farmer in Village – 2.

i) Would the farmer have to look for other kind of occupations to meet his needs?
Answer:
No need to look for other kind of occupations to meet their ends, but has to select proper crops that requires less water, proper methods that increase ground water, proper devices to use water discriminately.

j) How did the availability of water affect a small farmer at Village – 2?
Answer:
The availability of water affected the average household income at Village – 2 For them farming is not profitable. As their income is less than the life standards of these people will also be less.

Question 11.
How can wells be recharged ?
Answer:
Percolation pits helped in reacharging dried up bore wells. Dykes or barriers are constructed to build underground streams.

Question 12.
How would recharging dried up wells help farmers of Village – 2?
Answer:
In Village – 2 the recharged dried up wells build up under ground streams to tap underground water optimally.

Question 13.
What does the case tell us about a water resource and its effect on farmers?
Answer:
The case tells us that water should not be used indiscriminatly. Every water drop in the ground is important.

Question 14.
How do you think we can use water judiciously?
Answer:
The amount of fresh water is in small amounts only 2.5 – 2.75%. So we should use water carefully.

Question 15.
Why were farmers at Village – 1 at a better state than those at Village – 2?
Answer:
Farmers were at Village -1 at a better state than those at Village – 2 because the farmers of Village -1 have plenty of water to grow their crops.

Question 16.
How did farmers of Village – 2 and Village -1 recharge their ground water resources?
Answer:

1. The farmers of Village – 2 and Village -1 recharge their ground water resources by construction of soak pits.
2. The soak pits to tap rain water and by construction of dykes, they increased the ground water levels.

Question 17.
What other ways of restoration of a resource does the Kothapally case tell us about?
Answer:
Broad bed furrows land form and contour planting are the other ways of restoration of a resource.

Question 18.
What are some common means of restoration and conservation of water resource that we came across in the cases studied so far?
Answer:
Planting Gliricidia on field bunds to restrengthen and make soil nitrogen rich. Farmers were encouraged to use water resource jointly and irrigate land using micro irrigation techniques.

Question 19.
What do you think will happen if we do not take care of the sources of water?
Answer:
If we do not take care of water resources, they get replenished.

Question 20.
How do you think we will meet our requirements in future?
Answer:
We have to meet our requirements in future by

1. Desalenating the sea water
2. Restoring of ground water by recharging with rain water.
3. Getting cooperation from the neighbouring states and
4. Conserve water now for future.

Question 21.
Do you think we would have to depend upon other states or perhaps other countries as well?
Answer:
Yes, we would have to depend upon other states for water.

Question 22.
Could the amount of water used for irrigation in our state be reduced? How?
Answer:
The amount of water used for irrigation in our state could be reduced by following micro irrigation techniques like drip irrigation, sprinkles, etc., and by growing crops that require less amount of water.

Question 23.
Does cropping pattern have any role to play in reduction of water utilisation?
(Hint: Think of the case of Village – 2 and Village -1).
Answer:
Yes, cropping pattern have role to play in reduction of water utilisation. Broad bed furrow, land form and contour planting helps in reduction of water utilisation.

Question 24.
Do you think one needs laws for distribution of water and its use? Why/Why not?
Answer:

1. Yes, laws are needed for distribution of water and its uses.
2. Otherwise all the people may not have self discipline to conserve water.
3. As water is a key resource for life competition may arise between people or states or countries.
4. Laws help to control this kind of disputes and use it judiciously.

Question 25.
How much per cent of area do you think is irrigated by other sources of water?
Answer:
Five per cent of area in our state is irrigated by other sources of water.

Question 26.
Why is it important to recharge the ground water sources?
Answer:

1. Recharge of the ground water sources is very important.
2. This is because nearly 43% of irrigating land is getting water from ground.
3. Due to over drilling of bore wells and pulling out the water by using electric motors, the ground water level is decreasing day by day.
4. If it goes on without recharging, ground water becomes scarce.
5. It shows a vast impact on agriculture and the productivity will decrease.
6. Flourine level in ground water will increase.
7. Saline water may intrude in to the interior places of land and water becomes unfit for both drinking and agriculture.
8. Farmers have to drill the bore wells to the more depths which increase the losses for them.

Question 27.
Why do the rivers fail to benefit the state to an extent they should have?
Answer:
Rivers fail to benefit the state to an extent they should have. Because

1. There are no sufficient structures (dams) to store river water.
2. Over usage of water by the other states.
3. Geographically our rivers are flowing through the rocky and hill areas in most of the places in our state where it is difficult to make canals.
4. The government should plan for proper utilization of river water after scientific study with the help of expert engineers.

Question 28.
Since ground water resources are getting depleted at a fast pace what are the alternatives?
Answer:
Since ground water resources are getting depleted at a fast pace we have to construct percolation tanks to collect run off water. Water shed management projects should be adopted to renew the ground water levels.

Question 29.
River Godavari fails to provide water for the projects like Sri Rama Sagar in Telangana due to over usage of water by some other state. How should states and countries work to provide enough for all?
Answer:
States and countries should work to provide enough water for all by allotting water to other states or countries in an emicable atmosphere.

Question 30.
What would you do to motivate others to manage an important resource in your locality?
Answer:
To motivate others manage an important resource in my locality I will do the following activities:

1. I will explain the importance of resource and need for its proper management.
2. I will conduct the seminars on this issue.
3. With the help of my friends and teachers I will conduct some competitions like debate, essay writing, etc., on this issue.
4. I will plan some cultural activities such as songs, skits that explain the importance of managing the resource and exhibit them in the school and the village to motivate the village.

Question 31.
How did the villagers in Kothapally resort to sustainable management
Answer:

1. The villagers in Kothapally resort to sustainable management with the help of ICRISAT.
2. ICRISAT educated villagers by large and provided technical support for cost-efficient water storage and soil conservation structures.
3. The measures were community as well as individual farmer-based.
4. Fourteen water storage structures with the storage capacity of 300 to 2000 m³, 60 mini percolation pits, field bunding on 38 hectares were completed.
5. Twenty-eight dry open wells, near Nalla were recharged by building dykes in the Nalla and retaining the run off rain water in it.
6. A user group was formed for each water storage structure and the water collected was exclusively used for recharging the ground water to the dried well.
7. Broad bed furrow land form and contour planting was implemented to conserve soil and water.
8. Gliricidia plants are planted on the field bunds to strengthen the land, make the soil nitrogen rich.
9. Farmers were encouraged to use water resource jointly and irrigate land using micro-irrigation techniques.
10. Saplings of useful species were planted along the roads, field bunds and Nallas.

Question 32.
Why do you think forests are important?
Answer:
Forests are important because,

1. They are rich habitat for plants and animals.
2. They serve as a lung for the world.
3. They purify air, decrease carbon dioxide, global warming and green house effect.
4. Thus provide various valuable things such as wood, medicines etc.
5. They are providing raw materials for several industries.
6. They maintain ecological balance in nature.
7. They preserve the soil fertility.
8. They cause rains.

Question 33.
Observe a lawn in your area (if you have one) and see how it is maintained. Find out from the gardener the different types of plants that he removes from time to time. Do you think a farmer does the same thing on his farm?
Answer:
The gardener removes all the species of plants that grow in the lawn from time to time.
Farmer does the same thing on his farm. But the variation is all the plants are removed from lawn just for pleasant look whereas farmer remove only weed plants that compete with the crop plants for space, nutrients, water and sunlight. This is to increase the productivity of crop plants.

Question 34.
What do fossil fuels provide us?
Answer:

1. Fossil fuels provide us energy.
2. This energy can be used for various purposes such as running vehicles, machinery in industries, etc.
3. They are also useful in the production of electricity.
4. They also provide petrochemicals which are helpful in the manufacturing of several products that include plastics, synthetic rubber, fabrics like nylon, medicines, cosmetics, waxes, cleaning products, medical devices, etc.
5. They also provide energy for cooking, lighting, etc.

Question 35.
Why do we need to conserve the fossil fuels?
Answer:

1. Fossil fuels are non-renewable resources.
2. If once they are used up, they never replenish again or take several thousands of years to replenish.
3. They become integral part of our life, that we cannot live without these.
4. So, we need to conserve fossil fuels so that we don’t run out of them.

Question 36.
Collect information about solar, wind, tidal and water power and prepare a scrap book.
(OR)
Collect information about conventional energy sources from internet and prepare a note on it.
Answer:
Solar energy: To use solar energy is to generate electricity from sun light. For this purpose special chemical substances which are sensitive to light have been developed.
When light falls on these substances small chemical current is generated in large amounts. This can be stored and used when needed.
Watches, calculators, street lamps have been invented which use the current produced by light falling on light sensitive material.
Wind Energy: Wind mills are in use for centuries especially for pumping water from wells.
In wind mills, wind rotates the blades of windmill and is used to move the piston and lift the water from the well.
Wind energy is being used to pump water and to run turbines for the production of electricity.
Tidal energy (Kinetic energy) : Large amount of energy (Kinetic energy) la stored In the waves especially In seas.
Special devices have been made to rotate as the water passes through them by the wave action.
This Is used to generate electricity.
Water power: Dams are constructed across the rivers water from the reservoir falls from a height on the turbines.
This water falls Is used to drive turbines to generate electricity. These are called hydro electric projects.

Question 37.
Ask your teacher about nuclear energy and its impacts on ecosystem.
Answer:
Nuclear energy is produced by splitting the nucleus of an atom of elements like uranium or plutonium. This process Is called fission.
Another process for production of nuclear energy Is by fusion. In this process two nuclei of the same elements are fused with one another. In this process more energy is produced than by fission.
The energy Is produced as heat. This Is used to produce steam which runs generators to produce electricity.

Question 38.
Think why disasters like Uttarakhand happened?
Answer:

1. Uttarakhand and Himachal Pradesh are two hill states that were stuck by extreme rains in 2013.
2. Heavy rainfall has wrecked havoc on the region because of fragile nature of Himalayan range and poor soil stability in its deep steps. But it is the man made factor that has compounded the scale of the disaster.
3. Unabated expansion of hydro power project and construction of roads to accommodate ever-increasing tourism especially religious tourism are also major causes for the unprecendented scale of devastation.
4. The valleys of Yamuna, Ganga and Alakananda attract heavy traffic of tourists. For them, government has to construct new roads and widen the existing ones.
5. A new mountain range like Himalayas will remain study if not tampered much. But the huge expansion of trade and transport is bringing the mountains in Uttarakhand down.
6. Study should be conducted to assess the carrying capacity of the Himalayas and development should be planned accordingly.

Threat from dams: The Ganga in upper reaches has been engineers’ play ground. The central electrical authority and Uttarakhand power department have estimated the rivers hydrolytic potential at some 9000 muc and planned 70 odd projects on its tributaries. In building these, key tributaries have been modified through diversions through tunnels or reservoirs.

Question 39.
Do you think it is necessary to have a lot of lighting for decoration during celebrations?
Answer:
No, it is not necessary to have a lot of lighting to decorate an occassion of celebration. It is mere waste of electricity and money. We should conserve electricity for proper use.

Question 40.
What other things could you reuse to save our resources?
Answer:

1. Glass, paper, wax, plastic, etc., can be reused to save our resources.
2. Recycle: By recycling the waste materials we can reduce pollution.
   Ex : Plastic recycling is a tricky process and can cause havoc.
3. Plastic needs to be carefully stored before it can be processed.

Question 41.
Why should one sort wastes carefully before discarding them from home?
Answer:

1. Before discarding the waste materials we should sort out the reusable things and recycling things.
2. If it is undecayable waste like glass or plastic we can discard them or if they are the decayable waste we can prepare a compost pit to enrich the soil.

Question 42.
Often we keep a plastic bag in our dustbins to discard waste, is it a good practise?
Answer:

1. No, it is not a good practise to discard waste in a plastic bag.
2. When we threw the waste along with the plastic bag it takes hundreds of years for the plastic to get destroyed in the soil and the soil gets polluted.

Question 43.
Can international, national or state organisations alone manage a resource? Who are all involved in the whole process of management?
Answer:
Along with international, national or state organisations there is private organisation named International Union for the Conservation of Nature founded by private groups.

Question 44.
Suggest some ways in which you and your Mends would like to manage a resource.
Answer:
By practising four R’s-reduce, reuse, recycle and recover the things, preparation of recharging structures for water, protecting the wild life and habitats we can manage the resources.

Question 45.
Are we also an important resources of nature? How?
Answer:

1. Yes, we are also an important resources of nature.
2. Human beings, through the labour they provide and the organizations their staff are also considered to be resources.
3. The term human resources can also be defined as the skills, energy, talent, abilities, and knowledge that are used for the production of goods or the rendering of service.
4. In a project management context, human resources are those employees responsible for undertaking the activities defined in the project plan.

Question 46.
Find out the usage of water in litres per day in your home? Do you actually require that much water and how much water is enough in accordance with National standards?
Answer:

1. In my house 900 litres of water is being used per day at the average of 225 litres for a person per day (4 members family).
2. Actually this much water is not required.
3. We can conserve at least 400 – 500 litres of water at the average of 100 to 125 litres per head.
4. In India, the design of water supply system has been done using certain standards.
5. Currently the standard being used is BIS 1179 : 1993, reaffirmed in 1998.
6. According to this, for communities with a population between 20,000 to 1,00,000 – 100 to 150 litres per head per day can be considered.
7. For communities with population over 1,00,000 – 150 to 200 litres per head per day can be considered.
8. On the whole, at an average of 150 litres per head per day is enough in accordance with National standards.

10th Class Biology 10th Lesson Natural Resources Activities

Activity – 1

Study the different ways in which water is used, misused and recycled in the area where you stay. Prepare a questionnaire with the help of your friends and teacher and study at least five households in your locality for the same. Also explore and discuss ways to provide water for all.
Answer:
Ways in which water is used:

1. Drinking
2. Bathing
3. Washing clothes
4. Cleaning utensils
5. For plants in garden and agriculture, etc.

Ways in which water is misused:

1. Not closing the taps after using.
2. Contaminating the water.
3. Brushing near open taps.
4. Getting bath under shower.
5. Playing with water.

Ways in which water is recycled:

1. Allowing the water used in kitchen for garden.
2. Using the once used water to wash vehicles.
3. Using the water from bathing for toilet flush.
4. Washing hands in plant pots.

Questionnaire:

1. For what purposes water is being used in your home?
2. From where this water is being collected?
3. Are you using water only for the needed things?
4. Are you closing taps properly after using?
5. Are you getting shower bath?
6. Are you using more water than required for cleaning, bathing etc?
7. Are there any leaks in your water pipelines?
8. Are you recycling the once used water?
9. In what way are you recycling the water?
10. What measures do you suggest to conserve water and make it available for all?

Ways to provide water for all:

1. Wastage of water should be strictly minimised.
2. Washing hands in the plant pots.
3. Rain water should be directed into recharge pits.
4. Care should be taken to prevent leakage of water from pipes and taps.
5. Wash clothes in running water canals if possible.
6. Direct the kitchen water free from soap and detergents to the garden.
7. Use the soap and detergent water for toilet flush or cleaning vehicles.
8. Recycling of water can be done on large scale in towns and cities and can be utilised again.
9. Cooperation between the states through which a river passing is very essential for providing water for all.
10. People should be motivated in such a way that each drop of water is life and should conserve it.

Activity – 2
i) Find out how many different types of insects are present in and around your house.
Answer:
We find different types of insects present in and around our house.

ii) Do you find the same type of insects in all seasons ?
Answer:
No. We find different types of insects in different seasons.

iii) Make a chart of insects and note their occurrence for at least a week in each season.
Answer:
Ants – All seasons particularly in summer for collection of food.
Butterflies – Winter, summer – Collecting nectar
Honeybee – Winter, summer – Collection of honey.
Beetles – Winter, summer – Collection of food grains
Cockroaches – All seasons – Food and shelter

Activity – 3
Nowadays people are revolt against mining. Collect any such’ incident of our state or neighbouring states from your school library or newspapers and conduct seminar on it’s impact.
Answer:

1. People living in hill top hamlets in seven mandals of Visakhapatnam and East Godavari districts are up in arms against laterite mining in Nagulakonda hill range.
2. Laterite is a raw material used by cement factories.
3. Huge deposits of laterite worth hundreds of crore rupees are found in Nathavaram and Kowur mandals in Visakhapatnam and Pratthipadu, Yeleswaram, Sankhavaram, Routulapudi and Kotananduru in East Godavari.
4. All these mandals are technically coming under scheduled areas.
5. If the mining continues here, it will badly threaten the ecology of that area.
6. The tribal people in that area will lose their livelihood.
7. To reach the mining area road should be laid in the reserve forest area.
8. This leads to depletion of forest resources also.
9. Health of the local people will be badly affected due to the dust spread during mining.
10. Keeping all these in mind the tribal people are opposing the mining in that area.

 

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 9 Our Environment Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 9th Lesson Our Environment

10th Class Biology 9th Lesson Our Environment Textbook Questions and Answers

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Question 1.
What happens to the amount of energy transferred from one step to the next in a food chain?
Answer:

1. Energy is transferred along food chains from one trophic level to the next.
2. The amount of available energy decreases from one stage to the next.
3. This is because not all the food can be fully digested and assimilate.
4. Hair, feathers, insect exoskeletons, cartilage and bone in animal foods, cellulose and lignin in plant foods cannot be digested by most animals.
5. These materials are excreted or made into pellets of indigested remains.
6. Assimilated energy is available for the synthesis of new biomass through growth and reproduction.
7. Organisms also lose some biomass by death disease or annual leaf-drop.
8. Moreover at each tropic level, organisms use the most of the assimilated energy to fulfill their metabolic requirements – performance of work, growth and reproduction.
9. Most of the energy is lost in the form of heat during biological processes.
10. Only a small fraction goes to the consumer at next tropic level.

Question 2.
What do pyramids and food chain indicate in an ecosystem?
Answer:

1. The ecologists used the idea of pyramid to show relationship among organisms in an existing food chain.
2. Ecological pyramids are of three types. They are pyramid of biomass, pyramid of number, pyramid of energy.
3. Pyramid of biomass indicates the available biomass in an ecosystem; pyramid of number indicates the organisms present and pyramid of energy indicates the available energy in an ecosystem.
4. The food chain in an ecosystem indicates how energy is transferred from one organism to another.
5. The starting point of a food chain are producers and it ends with top carnivores.
6. A food chain represents a single directional transfer of energy.

Question 3.
Write a short note on pyramid of number for any food chain. What can we conclude from this pyramid of numbers?
i) tree ii) insect iii) woodpecker
(OR)
What is a pyramid of numbers? Write a brief note on the pyramid of numbers with the help of a block diagram.
Answer:
a.

1. The number of organisms in a food chain can be represented graphically in a pyramid of number.
2. Each bar represents the number of individuals at each tropic level in a food chain.
3. In the pyramid of numbers, from the first – order consumers to the large carnivores, there is normally an increase in size, but decrease in number.
4. For example, in a wood, the aphids are very small and occur in astronomical numbers.
5. The ladybirds which feed on them are distinctly larger and not so numerous.
6. The insectivorous birds which feed on the ladybirds are larger still and are only present in a small numbers, and there may only be a single pair of hawks of much larger size than the insectivorous birds on which they prey.

b.

1. In the given pyramid, the producer is a large tree, primary consumers are small
   insects which are numerous in number and secondary consumers are woodpeckers which are comparatively less in number than insects.
2. From this pyramid of number, we can conclude that sometimes the pyramid of numbers does not look like a pyramid at all.
3. This could happen if the producer is a large plant or if one of the organisms at any tropic level is very small.
4. Whatever the situation, the producer still goes at the bottom of the pyramid.

Question 4.
What is biomass? Draw a pyramid of biomass for the given food chain.
i) grass leaves ii) herbivores iii) predators iv) hawk
Answer:

1. Biomass is organic material of biological origin that has ultimately derived from the fixation of carbon dioxide and the trapping of solar energy.
2. This includes trees, shrubs, crops, grasses, algae, aquatic plants* agricultural and forest residues and all forms of human, animal and plant waste.
3. Any type of plant or animal material that can be converted into energy is called “Biomass”.
4. 

Question 5.
How is using of toxic material affecting the ecosystem? Write a short note on bioaccumulation and biomagnifications.
Answer:

1. Use of toxic materials such as pesticides, herbicides and fungicides creates new problems in the ecosystem.
2. As these toxic materials are often indiscriminate in their action and vast numbers of other animals may be destroyed.
3. Some of them may be predators which naturally feed on these pests, others may be the food for other animals.
4. Thus causing unpredictable changes in food chains and upsetting the balance within the ecosystem.
5. Some toxic substances have a cumulative effect.
6. Some of them are degradable, can be broken down into harmless substances in a comparatively short time usually a year.
7. Others are non-degradable which are potentially dangerous as they accumulate in the bodies of animals and pass right through food web.
8. This process of entering of pollutants in a food chain is known as “Bioaccumulation”.
9. The tendency of pollutants to concentrate as they move from one tropic level to the next is known as “Biomagnifications”.

Question 6.
Should we use pesticides as they prevent our crop and food from pests or we should think of alternatives? Write your view about this issue and give sound reason for your answer.
(OR)
Why should we think of alternatives to pesticides? Give reasons.
Answer:

1. We should think of alternatives. This is because these pesticides are toxic chemical whose usage leads to Bioaccumulation and Biomagnifications.
2. When we use pesticides, they prevent our crop and food from pests effectively but indiscriminately destroys a vast number of other animals.
3. This is causing unpredictable changes in food chains and upsetting the balance within the ecosystem.
4. Most of the chemical pesticides that contain mercury, arsenic or lead are non -degradable.
5. They enter into food chain, accumulate in the bodies of animals and pass right through food web.
6. Being further concentrated at each step until animals at the top of the pyramid may receive enough to do considerable harm.
7. This is one of the reasons for ever decreasing number of butterflies, bees, small and large birds.
8. Some of the pesticides are nerve poisons and might bring about changes in behaviour.
9. As the human beings are at the end of the food chain, these pesticides may get accumulated in our bodies also. This shows some adverse effects on us, when their concentration becomes sufficiently high.

Question 7.
What is a tropic level? What does it represent in an ecological pyramid?
Answer:

1. The various steps in a food chain at which the transfer of food takes place is called tropic level.
2. Tropic level means the feeding level of the organism.
3. In an ecological pyramid, the first tropic level represents the primary producers, and their number, biomass or energy.
4. Second tropic level represents the herbivores or primary consumers and their number, biomass or energy.
5. The tropic level represents the lower carnivores or secondary consumers and their number, biomass or energy.
6. The fourth tropic level represents the higher carnivores or tertiary consumers and their number, biomass or energy.

Question 8.
If you want to know more about the flow of energy in an ecosystem, what questions do you ask?
Answer:
I will ask the following questions to know more about flow of energy in an ecosystem.

1. How does the energy flow in an ecosystem from one organism to other?
2. Is the energy transformation from one level to other 100% efficient?
3. What per cent of energy transfers from one level to other?
4. What happens to the remaining energy?
5. How does the ecosystem lose its energy during energy transformation?
6. Which tropic level in an ecosystem has more energy and which has less?
7. What is the ultimate source of energy in an ecosystem?

Question 9.
What will happen if we remove predators from food web?
Answer:

1. Removal of organisms from any tropic level of a food chain or food web disturbs the ecosystem and leads to ecological imbalance.
2. If we remove predators from food web, the prey population will increase enormously as there is no natural control over them.
3. The producers population will decrease rapidly as the organisms feeding on them increase.
4. After few generations the prey population also begins to decrease as some of the preys begin to die due to starvation.
5. Some adaptations may also be developed by the organisms to bring the ecological balance.
6. But it may take some generations, till that the ecosystem will be disturbed and imbalanced.
7. For example, if we remove all the predators (carnivorous) from a forest ecosystem, the herbivorous animal population will increase as there are no carnivores to hunt them.
8. As a result plant population will decrease as the ever increasing herbivores feed more and more on plants.
9. After some generations the herbivore population begins to decrease as the decreasing number of plants are not sufficient to feed.
10. Then some herbivorous animals may adapt to feed on other herbivores to increase their survival.
11. Then scope for survival will increase for plants again which leads to ecological balance.
12. But this may take lot of time to evolve new predators and to form ecological balance.

Question 10.
Observe a plant in your kitchen garden, and write a note on producer-consumer relationship.
Answer:
When I observe a plant in kitchen garden, I came to know the following things.

1. Though it may be relatively small, a garden is a complete ecosystem.
2. It has the same components as any other large and elaborate ecosystems had.
3. The plant in a kitchen garden is a producer as it produces their own food from sunlight.
4. There are two types of consumers in this ecosystem, a) Primary consumers and b) Secondary consumers.
5. Primary consumers feed on plants. This tropic level consists of caterpillars, bees and butterflies.
6. Secondary consumers feed on primary consumers. This tropic level consists of birds, garden lizards and spiders.
7. Fungi, bacteria, insects and worms make up decomposers.
8. The producer and consumer relationship can be shown in the following food chain.
   Plant → Plant eaters such as caterpillars, bees, butterflies → Meat-eaters such as birds, garden lizards, spiders
   Producers → Primary consumers → Secondary consumers
9. The pyramid of number appears like this.
   
10. The pyramid of Biomass appears like this
    
11. The pyramid of energy appears like this
    

Question 11.
What type of information do you require to explain the pyramid of biomass?
Answer:
To explain the pyramid of biomass, we require the following information.

1. The type of ecosystem.
2. Producers in the ecosystem.
3. Primary consumers in the ecosystem.
4. Secondary consumers in the ecosystem.
5. Tertiary consumers in the ecosystem.
6. Number of organisms at each tropic level.
7. Size of organisms at each tropic level.
8. Weight of organisms at each tropic level.
9. All forms of waste produced at each tropic level and
10. In total, total amount of biomass produced at each tropic level.

Question 12.
Draw a pyramid of numbers considering yourself sis top level consumer. Pyramid of numbers
Answer:
Pyramid of numbers
Ex: 1

Ex: 2

Question 13.
Prepare slogans to promote awareness in your classmates about eco-friendly activities.
All the living things have the right to live on this earth along with us. Prepare slogans to promote awareness in public about the conservation of biodiversity.
(OR)
Which slogans do you prefer to promote awareness in your locality about eco-friendly activities?
Answer:

1. Live and let live.
2. If we protect the environment, it protects us.
3. Conserve nature – Conserve life.
4. Save mother earth.
5. Earth needs you.
6. Go ecofriendly.
7. Clean the environment, live happily.
8. Heal our planet! Turn it into a better planet.
9. Plant a tree for your environment.
10. Think ecofriendly and live ecofriendly.
11. Earth enables you to definitely stand. Allow it to stand the actual way it is.
12. You’ve only got one planet. Don’t trash it.

Question 14.
Suggest any three programmes on the prevention of soil pollution in view of avoiding pesticides.
(OR)
Suggest any four eco-friendly methods for prevention of soil pollution in view of avoiding pesticides. (OR)
In your area, soil is polluted by the enormous usage of pesticides. Suggest any two programmes for the prevention of soil pollution.
Answer:
To prevent the soil pollution caused by pesticides following programmes should be implemented.

1. Rotation of crops :
   1. Same crop should not be grown in the same field in successive seasons.
   2. Rotation of crops reduce occurance of pests and damage due to pests will be decreased.
2. Biological control: Introducing natural predator or parasite of the pest.
3. Sterility: Sterilising the males of a pest species reduces the population of pests.
4. Genetic strains: The development of genetic strains which are resistant to certain pest.
5. Studying the life histories of the pests: When this is done it is sometimes possible to sow the crops at a time when least damage will be caused.

Choose the correct answer.

1. What does a food chain always start with?
   A) The herbivore
   B) The carnivore
   C) The producer
   D) None of these
   Answer: C
2. Which of the following do plants not compete for?
   A) Water
   B) Food
   C) Space
   D) All the above
   Answer: B
3. Ban all pesticides, this means that
   A) Control on the usage of pesticides
   B) Prevention of pesticides
   C) Promote eco-friendly agricultural practices
   D) Stop biochemical factories
   Answer: C
4. According to Charles Elton
   A) Carnivores at the top of the pyramid herbivore
   B) Energy trapping is high at the top of the pyramid
   C) No producers at the top of the pyramid
   D) A and C
   Answer: D

10th Class Biology 9th Lesson Our Environment InText Questions and Answers

Question 1.
Are all terrestrial ecosystems similar?
Answer:

1. No. All the terrestrial ecosystems are not similar.
2. Basing on variations in climatic conditions such as rainfall, temperature and the availability of light, there are various kinds of ecosystems.
3. The major types of terrestrial ecosystem are
   1. Tundra,
   2. Coniferous forest,
   3. Deciduous forest,
   4. Savannah,
   5. Tropical forest and
   6. Deserts.

Question 2.
If we want to show a food chain consisting of grass, rabbit, snake and hawk then connect the given picture of organisms by putting arrows and make a food chain.
A) Name the producers and consumers in the above food chain.
B) Try to guess what does the arrows marked by you are indicate?
C) Identify at least four other food chains from your surroundings. Name the producers and different levels of consumers in those food chains.
Answer:
Grass → Rabbit → Snake → Hawk
A) In the above food chain grass is the primary producer. Rabbit is the primary consumer, snake is the secondary consumer and hawk is the tertiary consumer.
B) The arrows indicate the flow of energy from one organism to another. So these are always pointed from the food to the feeder.
C)

1. Plant → insect → frog → bird
2. Plant → insect →  frog → snake
3. Aquatic plants → insects → fish → crane
4. Plant → mice → snake → vulture
5. Plant → aphids → spiders → birds

Question 3.
Why do most of the food chains consists of four steps?
Answer:

1. Most of the food chains are quite short and mostly consists of four steps.
2. This is because only 10% of the energy present in a tropic level transfers to the other tropic level.
3. Remaining energy is dissipated as heat produced during the process of respiration and other ways.
4. Thus about three steps in a food chain very little energy is still available for use by living organisms.

Question 4.
Why do the number of organisms get decreased as we move from producer to different level of consumers?
Answer:

1. As we move from producers to different levels of consumers the energy available will decrease gradually.
2. Only ten per cent of the energy present in one tropic level transfer to another tropic level.
3. Biomass also decreases gradually as only 10 – 20% of the biomass is transferred from one tropic level to the next in a food chain.
4. As there is less energy & less biomass available at top levels, number of organisms also less, generally.
5. So, the number of organisms get decreased as we move from producer to different level of consumers.

Question 5.
Draw the pyramid of number for the following food chains.
i) Banyan → insects → woodpecker
ii) Grass → rabbit → wolf
A) Are the pyramid of number having same structure in both of the above two cases as compare to the example given in the earlier paragraph?
B) If there is a difference, then what it is?
Answer:

A) No. The pyramid of number in the above two cases doesn’t have the same structure as compared to the example given in the textbook.
B)

1. In the example (given in the textbook), number of organisms at producers level is more. This number gradually decreased in consumers level step by step. So the pyramid of number formed has typical pyramid shape with broad base and the narrow apex.
2. But in the first case given here, on a single Banyan tree, a large number of insects live and feed. These insects become food for few Woodpeckers. So producers number is less than primary and secondary consumers, and secondary consumers are less than primary consumers. So the pyramid of number does not look like a pyramid. It consists of narrow base, broad middle part and medium apex.
3. In the second case, grass which are large in number become food for few rabbits. Rabbit provides food for several wolves which are comparatively less in number than grass. So primary consumers are less in number than secondary consumers and producers. So the pyramid of number for this food chain also does not look like a pyramid. It consists of broad base, narrow middle part and medium apex. Thus it differs from case (i) also.

Question 6.
Think why the pyramids are always upright?
Answer:

1. In ecology not all the pyramids are always upright.
2. Pyramid of number may be upright, inverted or partly upright.
3. Pyramid of biomass may be upright or inverted.
4. But the pyramid of energy is always upright.
5. This is because energy will decrease when we move from producers to the high level consumers.
6. Only 10% of the energy from one tropic level transfers to the other through food chain.
7. So the energy at base is more, gradually decreases, and very less at the top.
8. As a result the energy pyramid is always upright.

Question 7.
Observe the data given in the following table.

Classes	Area in 1967(Km2)	Area in 2004 (Km2)
Lake – water spread area	70.70	62.65
Lake with sparse weed	0	47.45
Lake with dense weed	0	15.20
Lake-liable to flood in rainy season	100.97	0
Aquaculture ponds	0	99.74
Rice fields	8.40	16.62
Enchrochment	0.31	1.37
Total	180.38	180.38

i) In which year lake-water spread area is more? Why?
Answer:
In the year 1967. Because lake was not brought under cultivation.

ii) How do you think weeds are more in the lake?
Answer:
Excessive nutrient addition, especially from anthropogenic sources, led to explosive weed growth. Ex: Eichornia, pistia.

iii) What are the reasons for decrease in lake area?
Answer:

1. In 1996, almost entire lake was brought under cultivation.
2. Industries came along in ever growing intensity in the catchment area of the lake.

iv) How do the above reasons lead to pollution?
Answer:

1. Consequently, the drains and rivulets carry substantial quantity of various types of pollutants into the lake.
2. The major sources of pollution are agricultural runoff containing residues of several agrochemicals, fertilizers, fish tank discharges, industrial effluents containing chemical residues.

v) How was the threat to the lake due to pollution discovered?
Answer:

1. The water of the lake turned alkaline in nature, turbid, nutrient rich, low in dissolved oxygen and high in biochemical oxygen demand.
2. Water borne diseases like diarrhoea, typhoid, amoebiasis and others are said to be common among the local inhabitants who are unaware of the state of pollution in the lake water.
3. Vector borne diseases were also increased.

vi) What could be the reasons for the migration of birds to this lake?
Answer:
To avoid extreme cold weather conditions in Northern Asia and Eastern Europe birds migrate to Kolleru lake.

Question 8.
Observe the following table showing different activities in the lake and their influence.
Legend:
(+) means has influence on the mentioned problem
(-) means has no influence on the mentioned problem
i) What are the factors that affected the number of migratory birds to decrease?
Answer:
Aquaculture practices.

ii) Do you find any relationship between biological and physical problems?
Answer:
Yes. Aquaculture practices have influence on these problems.

iii) What are the reasons for chemical problems ?
Answer:
Agricultural practices, aquaculture practices, industrial activities and human activities are the reasons for chemical problems.

iv) What happens if the dissolved oxygen reduce in lake water ?
Answer:
If the dissolved oxygen reduces in lake water, sufficient amount of oxygen will not be available to organisms that live in the lake.
This leads to the death of organisms in the lake.

v) Is BOD of turbid and nutrient rich water high or low? What are its consequences?
Answer:
High. Its consequences are water borne diseases and death of organisms.

vi) People living in catchment area of Kolleru faced so many problems. Why?
Answer:
Vector borne disease increased. The lands adandoned are useless for agriculture.

Question 9.
Name any two pesticides / insecticides you have heard about.
Answer:
DDT, Aldrin, Malathian, Altrazine, Monocrotophos, Endosulphan etc.

Question 10.
How are the food grains and cereals being stored in your house and how dojyou protected them from pests and fungus?
Answer:
To protect food grains and cereals from pests and fungus, we will follow the following rules in our house.

1. First of all we will dry and clean our grain before storing.
2. We will avoid moisture in bagged grains by storing them on wooden structures, bamboo mats or polythene covers.
3. We use domestic bins or improvised storage structures such as Gaade, Kotlu, Paatara, RCC bins and flat bottom metal bins etc.
4. We fumigate the storage room with Ethylene Di-bromide (EDB) ampoules to avoid insect damage.
5. We use anticoagulant for rat control in houses.

Question 11.
Where from pollutants enter to the water sources?
Answer:
The used water from industries and run off water containing agricultural effluents bring pollutants into water sources. Municipal and domestic sewage also pollute water sources.

Question 12.
How can you say fishes living in water having heavy metals in their bodies?
Answer:
The bioaccumulation of heavy metals in tissues of fish particularly in liver, kidney and gills were analysed and found their presence.

Question 13.
Researchers found that pollution levels increase during monsoon season. Why they found so?
Answer:

1. Pollution levels increase during monsoon season in water bodies.
2. During monsoon season heavy rainfall occurs.
3. The rain water brings residues of agrochemicals, fertilizers and different types of organic substances, municipal and domestic sewage.
4. Hence pollution levels increase in monsoon season.

Question 14.
Why did people also suffer from various diseases after consuming fishes living in local water reservoir?
Answer:

1. The heavy metals could find their way into human beings through food chain.
2. This bioaccumulation cause various physiological disorders such as hypertension, sporadic fever, renal damage, nausea etc.

Question 15.
What is the food chain that has been discussed in the above case?
Answer:
The food chain discussed in the above occurrence is Crops → Locust → Sparrow → Hawk.

Question 16.
How did the campaign disturb the food chain in the fields?
Answer:

1. Crop yields after the campaign were substantially decreased.
2. Though the campaign against sparrows ended it was too late.
3. With no sparrows to eat the locust populations, the country was soon swarmed.
4. Locust coupled with bad weather led to the great Chinese famine.

Question 17.
How did these disturbances affect the environment?
Answer:

1. The number of locust increased.
2. Use of pesticides against locust population further degraded the land.

Question 18.
Is it right to eradicate a living organism in an ecosystem? How is it harmful?
Answer:

1. No, it is not right to eradicate a living organism in an ecosystem.
2. It disturbs the existing food chain.

Question 19.
Were the sparrows really responsible? What was the reason for the fall in crop production?
Answer:

1. No, the sparrows were not really responsible for the loss of food grain.
2. With no sparrows to eat the locust population crops were damaged and this led to fall in crop production.

Question 20.
What was the impact of human activities on the environment?
Answer:

1. The human activities badly affected the environment.
2. Use of pesticides against the pest degraded the land.

Question 21.
What do you suggest for such incidents not to occur?
Answer:

1. I suggest to use organic manures and organic insecticides to kill the insects.
2. Rotation of crops is the best method to protect the crops from pests.
3. We should not kill any organism on this earth because every organism has a role to play.
4. Think before you start action.

10th Class Biology 9th Lesson Our Environment Activities

Activity – 1

Observe any water ecosystem in your surroundings and identify the different food chains and food web operating in this ecosystem. Write the following details in your notebook.

WORKSHEET

1. Names of the students in a group: ——————— Date: ———–
2. Name of the ecosystem: ———————
3. Topography: ———————
4. Names / Number of plants (producers) identified: ———————
5 Names / Number of animals identified: ———————
6. Identify the different types consumers and name them & mention their number below :
Herbivores (Primary consumers): ———————
Carnivores (Secondary consumers): ———————
Top carnivores (Tertiary): ———————
7 Food relationships among them: food habits/preferences: ———————
8 Show / draw the different food chains: ———————
9. Showcase the food web: ———————
10. List out all abiotic factors existing in the ecosystem: ———————
( A check list can be given, and asked to tick)
11. Is there any threat to the ecosystem ? Yes / No ———————
If yes, what ? and how ? ———————
Suggest few remedial measures ———————
Answer:
Student’s Activity.

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 7 Coordination in Life Processes Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 7th Lesson Coordination in Life Processes

10th Class Biology 7th Lesson Coordination in Life Processes Textbook Questions and Answers

Improve your learning

Question 1.
What do you mean by hunger pangs?
Answer:

1. When glucose levels in the blood fall, hunger pangs occur in the stomach.
2. Ghrelin hormone is secreted in the stomach when it goes empty.
3. Ghrelin is secreted from certain cell walls of the stomach.
4. Hunger contractions (hunger pangs) start to occur in the stomach due to secretion of ghrelin hormone.
5. Hunger pangs continue up to 30 – 45 minutes.
6. An increase in Ghrelin levels results in sensation of hunger and motivation to consume food.

Question 2.
What are the organ systems involved in the digestion of food which we eat?
Answer:
The organ systems involved in the digestion of food are:

1. endocrine system,
2. nervous system,
3. muscular system,
4. circulatory system and
5. excretory system.

Question 3.
Rafi said smell also increases our appetite. Can you support this statement ? How?
Answer:

1. Yes. I support the statement made by Rafi that smell also increases our appetite.
2. When we smell, the air borne substances get dissolved in the watery film of nasal mucus.
3. The chemoreceptors which are otherwise called olfactory receptors present in the nose trigger signals in the form of nerve impulses to the brain where the smell is detected.
4. However interactions between the senses of taste and smell enhance our appetite.

Question 4.
Write a note on peristalsis and sphincter function in the stomach.
Answer:
A) Peristalsis functions in stomach:

1. Contraction and relaxation of the muscles present in the stomach bring in a wave-like motion called peristalsis.
2. The contraction of the stomach muscles squeeze and mix the food with the acids and juices of the stomach.
3. Mechanical mixing of food in stomach occurs by peristalsis. This allows the mass of food to further mix with the digestive enzymes.
4. Peristalsis in stomach is involuntary and under the control of the autonomous nervous system.

B) Sphincter functions in the stomach:

1. Pyloric sphincter is present at the opening of the stomach into the duodenum (small intestine).
2. The pyloric sphincter allows only small quantities of food into duodenum at a time.

Question 5.
Observe the given part of the digestive system. What is it ? What is it’s role during digestion ?
Answer:

1. The given part is the LARGE INTESTINE in the human digestive system:
   
2. If creates peristaltic waves to send waste material called stool or faeces into the rectum.
3. In the large intestine water and mineral salts are absorbed from the waste material.
4. The faecal matter containing indigested food material, bile pigments and dead bacteria is formed in the large intestine.
5. It is stored in the rectum and expelled out of the body through the Anus.

Question 6.
Give reasons.
a) If we press the tongue against the palate, we can recognize taste easily.
Answer:
Reason :

1. When the tongue is pressed against the palate, the food substance is pressed against the opening of the taste bud letting it to reach the taste cells and triggering taste signals.
2. Finally, the taste is recognized in the brain.

b) We can’t identify taste when food is very hot.
Answer:
Reason:

1. Most of the taste buds on the tongue are killed when the food is hot.
2. This prevents the person from identifying the taste.
3. The perception of taste decreases when the temperature of the food rises beyond 35°C.
4. But we don’t pay attention to it because we become worried about the burning feeling.

c) If glucose level falls in blood, we feel hungry. (OR) €EI June 2015
We feel hungry if the blood glucose level falls down. 03 June 2019
Answer:
Reason :

1. When glucose levels in the blood fall, we get hunger pangs in stomach.
2. Hungry feeling start to occur in the stomach due to hunger generating signals that the brain from the stomach due to the secretion of the hormone ‘Ghrelin’.

d) Small intestine is similar to a coiled pipe. (OR)
Why is the small intestine long and coiled?
Answer:
Reason :

1. The length of small intestine is 7 meters long.
2. It is coiled so as to fit in the human body.
3. It is coiled to increase surface area and maximum nutrient absorption when food passes through it.

e) Urination increases when we take lot of fluids.
Answer:
Reason:

1. When we take lot of fluids, the kidneys will efficiently throw the water out by forming more urine than usual.
2. When there is excess water in the body, the brain usually produces less of a hormone called vasopressin.
3. This in turn causes the kidneys to produce a lot of dilute urine, until excess water is removed.

f) The process of digestion goes on in a person whose central nervous system has been largerly affected.
Answer:
Reason :

1. The enteric nervous system embedded in the walls of the long tube of our gut or alimentary canal control gut functions often independently of the brain.
2. The mass of neural tissue of enteric nervous system filled with important neurotransmitters reveals that it does much more than merely handle digestion.

Question 7.
Write differences between the following:
a) Bolus – Chyme
b) Small intestine – Large intestine
c) Mastication – Rumination
d) Propulsion – Retropulsion
Answer:
a) Bolus – Chyme:

Bolus	Chyme
1. Food that is masticated in the mouth.	1. It is the partially digested food in the stomach.
2. Alkaline in nature.	2. Acidic in nature.
3. Teeth and saliva turn food into bolus.	3. Stomach turn food by peristalsis into chyme.
4. Soft round ball of food that has been chewed.	4. It is the liquified part of food.
5. Food goes from mouth to stomach.	5. Food goes from stomach to small intestine.

b) Small intestine – Large intestine:

Small intestine	Large intestine
1. It is longer and has small width.	1. It is shorter and has broad width.
2. It is in between the stomach and large intestine.	2. It is the last part of the digestive system.
3. Digestive juices release from liver, pancreas.	3. Digestive juices are not released into large intestine.
4. Food is completely digested in it.	4. Absorption of water from the undigested food takes place in it.
5. It has three parts – duodenum, jejunum and ileum.	5. It has four parts – caecum, colon, rectum and anal canal.
6. Villi helps in absorption of digested food.	6. Villi are absent in large intestine.

c) Mastication – Rumination:

Mastication	Rumination
1. Grinding, chewing and shredding of food in the mouth by teeth is called mastication.	1. It is the chewing of cud that come from a part near the stomach of the animal to its mouth.
2. Mastication occurs only one time in the oral cavity.	2. Rumination allows food to undergo mastication more than once.
3. This is also known as chewing the food.	3. This is also known as chewing the cud.
4. It makes the food particles to tiny particles. Does not involve nutrient absorption.	4. It allows greater nutrients to be extracted and absorbed from the food particles.
5. It occurs in most of the animals (mammals), eg: Human being	5. It occurs only in ruminate animals. eg: Cow

d) Propulsion – Retropulsion:

Propulsion	Retropulsion
1. It is a means of creating force leading to movement of food.	1. It is a situation in which something (food) is pushed or forced backwards.
2. Peristaltic waves move food from one part to the other.	2. Small amount of chyme is pushed into duodenum, simultaneously forcing most of it back into the stomach.

Question 8.
How can you say that mouth is a munching machine?
Answer:

1. Mouth plays a major role in changing the texture of food.
2. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
3. The teeth grind, chew and shred the food.
4. The surface muscles of the jaw help in biting and chewing actions, while the deep muscles of the jaw move up, down, forward and backward during food mastication.
5. The teeth help in cutting and grinding while tongue movements evenly spread out the food and help in mixing it with saliva.
6. The muscles of the mouth enable the food to be pushed in the oral cavity and to be moved around.
7. By all this we can say that mouth is a munching machine.

Question 9.
What is mastication? Explain the role of different sets of teeth in this process.
Answer:
Mastication: Food can not be swallowed directly. So it must be grinded, chewed and shred. This process of grinding, chewing and shredding is called ’MASTICATION’.
Role of different sets of teeth in mastication:

1. In the oral cavity of human beings, 32 teeth and they are 4 different types to perform different functions.
2. They are a) Inscisors b) Canines c) Premolars d) Molars
   a) Inscisors: These are eight in number and have chisel shape. They have sharp edges and are specialized for cutting and biting the food.
   b) Canines: These are four in number and are with pointed edges- These are designed for piercing and tearing food.
   c) Premolars: These are eight in number and are also called cheek teeth. These are designed for crushing and grinding food.
   d) Molars: These are 12 in number. They are designed for crushing and grinding food.

Question 10.
During the journey of food from the mouth to stomach through oesophagus, how does muscular system coordinate in this process?
Answer:
Movement of food (bolus) from mouth to stomach through oesophagus is influenced by the coordination between muscular system and nervous system.
Muscular movement in mouth:

1. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
2. The surface muscles of the jaw help in biting and chewing actions while the deep muscles move the jaw up and down, forward and backward during mastication.

Muscular movement in oesophagus:

1. The wall of the oesophagus is made up of two kinds of smooth muscles.
2. The inner layer consists of circular muscles and the outer layer is of longitudinal muscles.
3. Contraction of circular muscles lead to narrowing of the oesophagus behind the bolus. So the food is squeezed downwards.
4. Contraction of the longitudinal muscles in front of the bolus widens the tube, results in shortening of particular part of oesophagus.
5. In this way food moves easily and enters the stomach. ,
6. Contraction and relaxation of oesophagus muscles bring peristaltic movements.

Question 11.
Is there any reason for the intestine to be coiled with many folds ? In what way it is helpful during the process of digestion? (OR)
Small intestine is similar to a coiled pipe. Give reason.
Answer:

1. Yes, there is a reason for the intestine to be coiled with many folds.
2. The coiled and folded nature of intestine slows down the passage of food along the intestine and afford an increased surface area for absorption.
3. It also increases the surface area for the intestine to increase the absorption of nutrients through finger-like projections villi.
4. The folded and coiled intestine absorbs nutrients and water more than they breakdown.

Question 12.
What is the function of peristalsis in these parts?
a) Oesophagus b) Stomach c) Small intestine d) Large intestine
Answer:
a) Oesophagus:
Peristalsis helps in pushing the food, down the oesophagus into the stomach.

b) Stomach:

1. Peristalsis helps in storing food, breaking down food down and mixing it with juices secreted by stomach lining.
2. Peristalsis in stomach helps in partial digestion of food.

c) Small intestine:

1. Peristalsis pushes the digesting food through small intestine.
2. It helps to mix the chyme to help in the digestive process.
3. Peristalsis also helps in absorbing nutrients from the digesting food into the blood.

d) Large intestine:
Peristaltic movements help to propel feces along the large intestine through colon, to the rectum for expulsion from the body.

Question 13.
How can you justify the enteric nervous system as the second brain of the gut?
(OR)
Write about the nervous system present beneath the digestive system.
Answer:

1. The enteric nervous system, the second brain consists of sheaths of neurons embedded in the walls of the long tube of our gut, or alimentary canal.
2. The second brain measures about nine meters to end from the oesophagus to the anus.
3. The second brain contains some 100 million neurons, more than in either the spinal cord or the peripheral nervous system.
4. This multitude of neurons in the enteric nervous system enables us to “feel” the inner world of our gut and its contents.
5. Enteric nervous system contains mass of neural tissue filled with important neurotransmitters.
6. This reveals that it does much more than merely handling digestion or inflict the occasional nervous pang of hunger.
7. Enteric nervous system stimulates and coordinates the breaking down of food, absorbing nutrients and expelling of waste.
   Thus equipped with its own reflexes and senses, the second brain can control several gut functions often independently of the brain.
8. Several scientists also believe that the enteric nervous system is a way too complicated to have evolved only to make sure things move through and out of our gut smoothly.
9. Hence we can justify that the enteric nervous system as the second brain of the gut.

Question 14.
Rajesh feels hungry upon seeing food. Sheela says no more food as she is not hungry. What makes Rajesh hungry and what suppresses Sheela’s hunger?
Answer:

1. When glucose levels in the blood fall, we get hunger pangs in the stomach. Feeling hungry lies in the physiology of blood circulation.
2. The secretion of the hormone GHRELIN starts in the stomach when it goes empty.
3. Hunger contractions start to occur in the stomach due to hunger generating signals that reach the brain from the stomach due to ghrelin.
4. So Rajesh effected with secretion of ghrelin in his stomach and he felt hungry when he saw food.
5. Sheela was not affected with secretion of ghrelin in her stomach. She felt that her stomach is full.
6. When we feel the stomach is full and there is no need of food any more, another hormone LEPTIN is secreted that supresses hunger.

Question 15.
How are taste and smell related?
(OR)
What is the relationship between taste and smell?
Answer:

1. Taste and smell are closely related.
2. This close relationship is most readily seen in how we perceive the flavours of food.
3. Anyone with severe cough and cold cannot make out the difference in the taste of certain food items.
4. Actually, what is really being affected is the flavour of the food , or the combination of taste and smell.
5. That is because not only the taste but also the food odours are being defected.
6. However, interactions between the senses of taste and smell enhance our perceptions of the foods we eat.
7. Smell of the food flavour gives a similar taste to food.

Question 16.
List out the sphincter muscles of the food canal you have observed and give a brief description.
(OR)
What are the different types of sphincter muscles present in the digestive canal?
Answer:
There are different sphincter “muscles in the food canal. They are :

1. Esophageal sphincter
2. Cardiac sphincter
3. Pyloric sphincter
4. Anal sphincter and
5. Ileocecal value or sphincter.

1. Esophageal sphincter:

1. This allows entry of bolus into the oesophagus,
2. It also reduces back flow from the oesophagus to pharynx.

2. Cardiac sphincter:

1. It is present where oesophagus meets the stomach,
2. It’s location is almost directly in front of the heart,
3. It allows food from oesophagus into the stomach.

3. Pyloric sphincter:

1. It is present at the opening called pylorus, located at the end of the stomach,
2. Pyloric sphincter allows only small quantities of food into duodenum at a time.

4) Anal sphincter:

1. It is located at the anus, the end of the digestive system,
2. The release of waste is controlled partly, voluntarily by anal sphincter.

5) Ileocecal value:

1. It is situated at the junction of the small intestine (ileum) and the large intestine (colon),
2. It’s function is to limit the colonic contents into the ileum.

Question 17.
What happens if salivary ducts are closed?
(OR)
What happens if saliva is not produced by salivary glands?
Answer:
If salivary ducts are closed the following consequences may occur:

1. If salivary ducts are closed saliva will not release into the mouth, the mouth becomes dry.
2. We can’t taste the food.
3. Saliva secretes an enzyme called salivary amylase which breaks down the carbohydrates in food into dextrose and maltose sugar.
4. If saliva is not secreted in the mouth carbohydrates remains unchanged digestion will not completed.
5. Due to absence of saliva food will not get moistened, chewing and swallowing becomes difficult.
6. If salivary ducts are closed, the salivary glands become swollen and it leads to pain.

Question 18.
If size and shape of small intestine is like oesophagus what will happen?
Answer:

1. If size and shape of small intestine is like oesophagus the height of the person should be more than 22 feet as the length of the small intestine is about 22 feet. So it will not fit in the human body.
2. For the complete digestion of the food to occur, it has to stay in small intestine for 3 to 4 hours.
3. Otherwise digestion will not be completed and nutrients are not absorbed into blood . in the small intestine.
4. The tube like nature of small intestine as that of oesophagus will not provide increased surface area for complete absorption of nutrients.

Question 19.
Prepare a questionnaire to understand nervous coordination in the digestion process.
(OR)
What are the questions you are going to ask your teacher about nervous coordination in the digestion process?
(OR)
Prepare a questionnaire for an interview with a doctor to understand the nervous coordination in the digestion process.
Answer:

1. What is enteric nervous system?
2. Why the enteric nervous system is known as second brain?
3. How nervous system plays an important role in digestion of food?
4. Which nervous system controls the release of saliva from salivary glands?
5. Which cranial nerve controls the movement of muscles in the jaw?
6. The mechanism for swallowing is under the control of?

Question 20.
What experiment do you perform to understand action of saliva on flour? Explain it’s procedure and apparatus that you followed.
(Activity – 7)
(OR)
i) Explain the procedure followed in the experiment conducted to understand the action of saliva on starch.
ii) What apparatus and chemicals are used to do this experiment?
(OR)
Write the experiment you have performed in your school laboratory to know the action of Saliva on flour. How did you test the pH of Saliva?
(OR)
Explain the experiment conducted by your teacher in your class to show the action of saliva on the starch.
Answer:
Aim: To understand the action of saliva on flour.
Apparatus:

1. Two test tubes
2. Water
3. Ata flour
4. Water glass and
5. Iodine solution.

Procedure:

1. A test tube is taken and half of the test tube is filled with water.
2. A pinch of flour is added.
3. To mix flour with water, test tube as shaken.
4. Few drops of flour mixture is taken in a watch glass and test for the presence of starch by putting a drop of diluted tincture Iodine in it.
5. A blue black colour confirms the presence of starch.
6. Divide the mixture into two equal halves by transferring it to another test tube.
7. Both the test tubes have the same amount of solution.
8. Add a teaspoon of saliva to one of the test tube and mark it.
9. Do not add anything in the other test tube.
10. After 45 minutes add a drop of dilute Tincture Iodine solution to test tubes containing the solutions.

Observation:

1. Saliva containing flour mixture becomes slurry. It doesn’t show any change.
2. But in the second test tube with only flour mixture turns blue colour.

Conclusion:

1. Saliva in the test tube converts flour into sugar. So no change is observe here.
2. In the second test tube containing only flour mixture turns blue black.

(OR)
i) Answer:

1. Add a spoon of starch to the water taken in a test tube to make starch solution. Starch solution is divided into two equal parts in two test tubes.
2. Add a little saliva to one of the above test tube and the other without adding saliva and keep them a side for some time.
3. Add a drop of dilute iodine to both the test tubes. The test tube added with saliva doesn’t turns to blue black because the starch is broken down into smaller units called sugar by the saliva.
4. The other part which is not added with saliva turns into blue black, as it has starch without any change.
   So this experiment proves saliva converts complex carbohydrates into simple sugars.

ii) Answer:
Test tubes, water glass, flour, iodine, saliva.

Question 21.
Suggest a simple experiment to prove the role of palate in recognizing taste.
(OR)
How do you prove that palate has a role in recognizing taste?
(OR)
“Taste is connected to the tongue and palate”. Write an activity to prove it and write your observations.
Answer:
Experiment to prove the role of palate in recognizing taste
Aim: To prove the role of palate in recognizing taste.
Apparatus: Sugar crystals, Stop watch.
Procedure:

1. Place some sugar crystals on the tongue.
2. Keep mouth opened and see that tongue does not touch the palate.
   
3. Record the time from the moment we placed the crystals on the tongue till we get the taste by using stop watch.
4. Now repeat the test by placing the sugar crystals on the tongue pressing it against the palate.
5. Record the time from placing sugar crystals to getting the taste.

Observation: From the above activity we know that taste can be identified easily when the tongue is pressed against the palate.
Result: We can easily identify the taste of the substance we can identify the taste of it in lesser time.

Question 22.
Collect information related to feeling hunger from your school library and prepare a note on it.
Answer:

1. Generally we feel hunger when our stomach goes empty.
2. When our stomach goes empty Ghrelin hormone is released and it causes the feeling of hunger.
3. As well leptin hormone also released, but it causes the feeling of suppression of hunger.
4. Not only these, when we saw a colourful and good smelling food, automatically we feel hunger. So, the sight of seeing a good food also causes feeling of hunger.
5. If the food doesn’t have good colour, texture, good smell we can’t eat, even though it is a good food.
6. All the feelings towards food are recieved by our eyes, nose, tongue.
7. From these, information is sent to brain, from there signals are sent to stomach and causes feelings either positive or negative.
8. Hormones are also responsible for most of the feelings of hunger.

Question 23.
Draw the block diagram of showing sensation of taste from food material to brain.
Answer:

Question 24.
Draw a neatly labelled diagram showing a peristaltic movement in oesophagus Explain the importance of mucus on the walls of food pipe.
(OR)
In the food pipe, the food bolus is propelled into the stomach by peristaltic movement Represent this action with a diagram.
Answer:
Importance of mucus on the walls of food pipe :

1. The walls of the food pipe secrete a slippery substance called mucus.
2. Mucus lubricates and protects the oesophgeal walls from damage.
3. This helps the food bolus to slide down easily.
4. Besides this the saliva in the bolus also helps in easy movement.

Question 25.
Draw a schematic diagram of villus in small intestinp. Explain how digestive system coordinates with circulatory system.
(OR)
Draw the diagram of villi in small intestine and lable its parts.
Answer:
Coordination of digestive system with circulatory system :

1. After the completion of digestion in small intestine, it enters into the blood through villi.
2. In blood the digested food gets oxidised after that energy is released.
3. Releasing of energy from fot^d occur only when it enter into the blood.
4. So, there is a great coordination between digestive and

Question 26.
The mere smell or sight of food stimulates hunger . Describe the process through a neat diagram.
Answer:

1. The mere smell even the mere sight of delicious food stimulates the hunger.
2. When we smell, the air borne substances get dissolved in the watery film of nasal mucus.
3. The chemoreceptors in nose are otherwise called olfactory receptors which trigger signals in the form of nerve impulses to the brain where smell is defected.
4. The amount of the neurosecretory protein hormone ghrelin in the blood increases as a result of visual stimulation images of food.
5. Hunger contractions start to occur in the stomach due to hunger generating signals that reach the brain.
6. It is believed that the diencephalon in fore brain and vagus nerve (10th cranial nerve) plays an important role in carrying these signals to brain.
7. Hunger pangs continue up to 30-45 minutes.
8. Increase ¡n ghrelin levels results in sensation of hunger and motivation to consume food.

Question 27.
With the help of a diagram show the movement of food from mouth to the stomach. What muscles and nerves are involved in the movement of food and what is this action called as ? (OR)
Draw a diagram of peristaltic movement of food in oesophagus of elementary canal. Write how it performs.
Answer:
The muscles involved in movement of food from mouth to stomach :

1. The circular muscles of the mouth enable the food to be pushed into the oral cavity and to be moved around.
2. The surface muscles of the jaw help in biting and chewing actions and move the jaw up, down, forward and backward.
3. Contraction and relaxation of circular and longitudinal muscles in the oesophagus bring in a wave like motion that propels the bolus into stomach by the action called peristalsis.
4. As the food approaches the closed ring of pyloric sphincter the surrounding muscles relax and allow the food to pass.
5. The muscles of the upper part of the stomach have to relax and accept large volumes of swallowed material.

Nerves involved in the movement of food:

1. The fifth cranial nerve has been found to control the movement of muscles in the jaw.
2. Peristalsis in oesophagus is under the control of autonomous nervous system.

Question 28.
Prepare a cartoon on Pavlov’s experiment with a suitable caption.
Answer:

Question 29.
How do you appreciate stomach as a churning machine? How does this coordination
Answer:

1. The stomach acts like a churning machine, churning the food around to break it into even smaller pieces.
2. Mechanical mixing of food in stomach occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall.
3. This allows the mass of food to further mix with the digestive enzymes.
4. Due to churning of food in stomach, a mixture that resembles thick cream called chyme is formed.
5. All the muscles in the stomach works with such a great coordination.
6. Hence we can call stomach as a churning machine.

Question 30.
There is a great variety in diversified life processes, express your feelings in the form of a poem.
Answer:

POEM
Life is a process of discomfort and pain.
Learn to handle it all with courage and sane
Remember the bliss waiting for you
Nutrition, excretion, respiration all are essential in our life.
Reproduction makes our species go on and on forever.
Autotrophs and heterophs are brothers.
Depend on each other In a systematic way.
So have courage to learn more tricks.
Search for happiness.
In life that survive.

Question 31.
Suggest any two important habitual actions to your friend while eating food, keeping in view of this chapter.
Answer:

1. Masticate the food thoroughly in the mouth.
2. Do not swallow food without chewing properly or do not eat in hurry.
3. Eat small quantities of food at regular intervals for efficient digestion and absorption of nutrients.
4. Eat the food that emit good smell and has good taste to eat.
5. Do not eat too hot and too cold items.

Fill in the blanks.

1. 3:2:1:2 is the ratio of our dentition. Here 1 represents ———–.
2. Large protein molecules are broken down in ———– of digestive tract.
3. ———– is the strong acid which is secreted during digestion.
4. Olfactory receptors present in ———– triggering signals to brain.
5. pH of saliva is ———– in nature.

Answer:

1. Canine
2. Stomach
3. HCl
4. Nose
5. Alkaline nature

Fill in the blanks with suitable words given below.

Fluctuations of hormone —–(i)—– levels results in sensation of hunger and motivation of consuming food. When you feel your stomach is full and there is no need of food any more. Another hormone —–(ii)—– that gets secreted suppresses hunger. When we take food into the mouth it has to be chewed thoroughly. For this purpose the —–(iii)—– muscles help in chewing actions, while the —–(iv)—– muscles of the jaw moves the jaw up,down, forward and backward during food mastication. The —–(v)—– nerve controls the muscles of the jaw. Under the action of —–(vi)—– nervous system Saliva is released by the salivary glands moistens the food to make chewing and swallowing easier. The salivary —–(vii)—– in the saliva breaks down the starch into sugars. As a result of chewing the food is transported into the oesophagus by the action of swallowing which is coordinated by the swallowing centre in the —–(viii)—– and the —–(ix)—–. The tongue which is gustatory recognizes the taste and —–(x)—– nerve plays an important role in sensation of taste.

Choose the right ones.
i) leptin, ghrelin, gastrin, secretin.
ii) ghrelin, leptin, secretin, gastrin.
iii) deep muscles, surface muscles, circu lar muscles, striated muscles.
iv) surface muscles, deep muscles, neck muscles, long muscles.
v) fifth cranial nerve, second cranial nerve, fifth facial nerve, spinal nerve.
vi) central nervous system, peripheral nervous system, autonomous nervous system.
vii) lipase, sucrase, galactase, amylase.
viii) medulla oblongata, cerebrum, 8th spinal nerve, cranial nerve, 7th cranial nerve.
ix) Pons varoli, brain stem, medulla oblongata, mid brain.
x) 6th cranial nerve, 5th cranial nerve, 10th cranial nerve, optic nerve.

Answer:
i) ghrelin
ii) leptin
iii) surface
iv) deep
v) fifth cranial
vi) autonomous
vii) amylase
viii) medulla oblongata
ix) brain stem
x) fifth cranial nerve

Choose the correct answer.

1. In which of the following situations you can taste quickly? [ ]
   A) Put sugar cristals on tongue
   B) Put sugar solution on tongue
   C) Press the tongue slowly against the palate
   D) Swallow directly without grinding and shredding
   Answer: C
2. Peristalsis is because of [ ]
   A) Contraction of longitudinal muscles
   B) Contraction of circular muscles
   C) Under control of autonomous nervous system
   D) Digestive secretions
   Answer: C
3. Sphincter that helps in opening of stomach into duodenum [ ]
   A) Cardiac
   B) Pyloric
   C) Anal
   D) Gastric
   Answer: B
4. Glucose and amino acids are absorbed through the following part of villus [ ]
   A) epithelial cells
   B) blood capillary
   C) lymphatic vessel
   D) all
   Answer: A
5. The region in brain portion that controls hunger signals [ ]
   A) medulla
   B) diencephalon
   C) cerebrum
   D) mid brain
   Answer: B
6. Human organism is an internal combustion machine because of …. [ ]
   (OR)
   Human being is an “Internal combustion machine” because he/she
   A) assimilation of energy from food
   B) liberate CO₂ during respiration
   C) expel waste food at the end state of digestion
   D) secrete powerful digestive juices
   Answer: A

10th Class Biology 7th Lesson Coordination in Life Processes InText Questions and Answers

10th Class Biology Textbook Page No. 145

Question 1.
How do we know that we need food?
Answer:
When we feel hungry then we know that we need food.

10th Class Biology Textbook Page No. 146

Question 2.
What plays a major role to identify stale food?
Answer:
Smell or odour plays a major role to identify stale food.

Question 3.
If you are having a tasty dish do you think the smell of it increases your appetite?
(OR)
Do the smell of tasty dish increases our appetite?
Answer:
Yes, the smell of tasty dish increases our appetite.

Question 4.
What are your observations after chewing cumin, sounf, potato and apple?
Answer:
If we chew cumin, sounf, potato and apple we observe in order to taste the food material the food should dissolve in saliva.

10th Class Biology Textbook Page No. 148

Question 5.
Are there any other sensation that affect taste?
Answer:
Temperature (hotness), coldness are the sensations that affect taste.

Question 6.
What happens to your taste sensation while sipping hot milk or tea?
Answer:
We find something more tasty while we sipping hot milk or tea.

Question 7.
What do you think could be the range of temperature for us to relish food items?
Answer:
30°C to 35°C could be the range of temperature for us to relish food items.

10th Class Biology Textbook Page No. 149

Question 8.
What do you think that would happen if the salivary glands did not function in our mouth?
Answer:

1. If the salivary glands do not function in our mouth, saliva will not release and the food do not get moistened and chewing it is difficult.
2. The taste of the food cannot be identified.
3. Carbohydrates in the food cannot be broken down and changed to dextrose and maltose molecules.

Question 9.
Suppose your taste buds were affected what would happen to your interest in haying food?
Answer:
If my taste buds were affected I cannot identify the taste of food and also loose interest in having food.

10th Class Biology Textbook Page No. 151

Question 10.
Does the level of saliva secretion change due to presence of food in the mouth?
Answer:
Yes, the level of saliva increases due to the presence of food in the mouth.

Question 11.
Can the process of chewing go on in the absence of saliva?
Answer:
Yes, the process of chewing go on in the absence of saliva. But it is very difficult to chew food and swallow it.

Question 12.
Does the saliva have any other roles to play?
Answer:
The enzyme present in saliva that is salivary amylase converts large molecules of carbohydrates into small molecules of sugar like maltose and dextrose.

Question 13.
What is the use of such an increase in surface area of food?
Answer:
It helps in more surface area for the enzyme to act.

Question 14.
What about the nature of medium for salivary amylase to act on food component?
Answer:
The nature of medium for salivary amylase to act on food component is alkaline.

Question 15.
If we swallow food material directly without mastication what will happen?
Answer:
If we swallow food material directly without mastication, the food will not get digest easily and completely.

Question 16.
Do you think the pH of our mouth changes?
Answer:
Yes, the pH of our mouth changes from acidic to alkaline by the release of saliva from salivary glands.

10th Class Biology Textbook Page No. 152

Question 17.
What are the different systems that contribute to the proper functioning of digestion in the mouth?
Answer:
Endocrine, muscular, nervous systems contribute to the proper functioning of digestion in the mouth.

Question 18.
After the digestive process in the mouth where does the food move to?
Answer:
After the digestion in the mouth the food move to oesophagus.

10th Class Biology Textbook Page No. 153

Question 19.
What are the systems that come into play for swallowing food?
Answer:
Skeletal system, nervous system and digestive systems come into play for swallowing food.

Question 20.
What does the schematic diagram tell us about the oesophagus?
Answer:
The schematic diagram of the oesophagus tells about its structure, secretion and function.

Question 21.
What kind of the tube is oesophagus?
Answer:
Oesophagus is a muscular and an elastic tube.

Question 22.
How does mucus help in passage of food?
Answer:
Mucus helps in lubricating and protecting the oesophageal wall and helps the bolus to slide down easily in the oesophagus.

10th Class Biology Textbook Page No. 154

Question 23.
What makes the movement of the food bolus in the oesophagus easy?
Answer:

1. Mucus helps the food bolus to slide down easily.
2. Peristaltic movements of the walls of oesophagus also make the movement food bolus in the oesophagus easy.

Question 24.
Why do you think the stomach is structured like a bag rather than a tube like an oesophagus?
(OR)
Why stomach is structured like a bag rather than like a tube?
Answer:

1. The food taken has to remain in the stomach for a long time for proper digestion with digestive juices and enzymes.
2. Different kinds of muscles churns the food by contraction and relaxation to form chyme.
3. If it was like a tube the food would just pass down without under going much changes and cannot remain in the stomach for long time.

Question 25.
What sets such processes into action?
Answer:

1. When the food is in the oral cavity, the nerves in the cheek and tongue are stimulated.
2. These carry messages in the form of nerve impulses to the brain.
3. They messages are transmitted from the brain, to the wall of the stomach, and stimulate the gastric glands to produce gastric juice.

10th Class Biology Textbook Page No. 155

Question 26.
What stimulates stomach muscle into action?
Answer:
The nervous system stimulates stomach muscle into action.

Question 27.
What causes the stomach to churn and mix the food?
Answer:
The contractions of the stomach muscles squeeze and mix the food with the acids and juices of the stomach.

Question 28.
Why should only a small quantity of food be passed from stomach to duodenum?
Answer:
For the complete digestion of chyme, only a small quantity of it be passed from stomach to duodenum.

Question 29.
What is involved in bringing about peristalsis?
Answer:
Contraction and relaxation of the muscles present in various parts of gut bring about peristalsis.

Question 30.
What is the direction of peristalsis? Which end of the gut does it begin?
Answer:
The direction of peristalsis is forward direction that is from mouth to anus.

Question 31.
What happens if the direction of peristalsis is reversed?
Answer:
If the direction of peristalsis is reversed the food present in the gut moves backwards.

10th Class Biology Textbook Page No. 157

Question 32.
Why do you think small intestine is long and coiled?
Answer:
The small intestine is long and coiled because the food has to stay for more time for complete digestion and absorption.

Question 33.
What process is involved in this process of absorption?
Answer:
Selective absorption of nutrients by the villi of small intestine is involved in absorption.

Question 34.
What is the relation between finger-like structures and paper folds?
Answer:

1. Finger-like structures increase the surface area.
2. The space inside the paper folds is very much high. So area is increased.
3. So increase in surface area is the relation between finger-like structures and paper folds.

Question 35.
What systems do you think are working together?
Answer:
The digestive system and circulatory system are working together.

Question 36.
Do you think those systems work together in the whole length of the digestive canal? Why / Why not?
Answer:
No, these systems are not working together in the whole length of the digestive canal. The digested food material is absorbed only in the small intestine but not elsewhere in the gut.

10th Class Biology Textbook Page No. 158

Question 37.
Often you may have experienced that if you have tension for some reason you start having loose motions. What does this show us?
Answer:
If we are tensed for some reason, the enteric nervous system or second brain loses control over the gut. Hence without our intervention, loose motions occur.

10th Class Biology Textbook Page No. 159

Question 38.
What moves out of the gut?
Answer:
The indigested food material moves out of the gut.

Question 39.
Two major pathways of waste expulsion are shown above. Which of the two do you think happens exclusively through the gut?
Answer:
Indigested food matter is expelled in the form of stool from the gut.

Question 40.
What controls the exit of stools from the body?
Answer:
The two muscular layers present In the anal sphincter control the exit of stools from the body.

Question 41.
Do you think the control is voluntary? Why / Why not?
Answer:
Yes, the control is voluntary in adults and it is involuntary in infants.

Question 42.
Did we have a sphincter in any other part of the digestive canal? Where was it?
Answer:
Yes. We have a sphincter at the opening where stomach opens into duodenum (small intestine).

10th Class Biology Textbook Page No. 160

Question 43.
What is the fate of the digested substances that move into blood from the intestine?
Answer:
The digested substances reach each cell of the body through circulatory system. There it gets oxidised and release energy.

Question 44.
Where is the energy stored?
Answer:
The energy is stored in the cells as ATP.

Question 45.
Which system do you think will remove the excess salts from our body?
Answer:
The excretory system remove the excess salts from our body.

Question 46.
What would be the path of salt removed from gut to the outside of our body?
Answer:

1. The digested food containing salts will be absorbed into the blood stream in small intestine.
2. The circulatory system supplies this to kidney through renal artery.
3. In the kidney salts are filtered and sent out of the body along with urine.
4. Some of the salts also supplied to the skin. They will be sent out of the body in the form of sweat.

10th Class Biology 7th Lesson Coordination in Life Processes Activities

Activity – 1
Observe the following table, identify and tick those options that you think makes you feel hungry.
Table

Smell of food	Taste of food	Sight of food	Being tired and exhausted	Need of food	Thought of food
✓	✓	✓	✓	✓	✓

i) What stimulates hunger?
Answer:
Smell of food, sight of food and need of food stimulates hunger.

ii) What would be the result of stimulation of hunger?
Answer:
Hunger pangs occur in the stomach.

iii) Which system do you think would send the signals to make us realize that we are hungry?
Answer:
Nervous system.

iv) What kinds of controls are exercised during sensation of hunger? Are they hormonal or nervous or both?
Answer:
They are both hormonal and nervous.

v) Can you suggest any four systems involved in the process of generating hunger sensation?
Answer:
Digestive system, Endocrine system, Circulatory system and Nervous system.

Activity – 2
Observation of how our taste is affected by the sense of smell. (OK) How our taste is affected by the sense of smell?

1. First, close your nose with your fingers.
2. Pop in some zeera in your mouth and chew it for some time.
3. After that chew some sounf.
4. Could you recognise the taste?
5. How long it taken to know the taste?
6. After sometime wash your mouth and repeat the activity by chewing a piece of an apple followed by a potato (remember to close your nose)

Could you know the taste of both or did it taste the same? Why?
Answer:
No, because taste buds couldn’t send the taste signals to brain.

Observation :

1. We can taste the food that is in the form of liquid only.
2. Only after the dissolved food enters into the cup like taste buds, the sense of taste is carried to the brain for analysis. Then only we will know the taste of food material.
3. Similarly olfactory receptors which trigger signals in the form of nerve impulses to the brain where smell is detected.

i) What happens when we put a food material in our mouth?
Answer:
Our mouth salivates.

ii) Name the parts in the mouth that help us to taste food.
Answer:
Papillae (taste buds), palate.

Activity – 3

1. Take a pinch of asafoetida powder/garlic and rub it on hand kerchief/tissue paper.
2. Close your eyes and smell it.
3. Then try to identify taste of different types of food materials with the help of your friend.

i) Does garlic have a stronger scent than apple? How do you think the stronger scent affect your sensation of taste?
Answer:
Yes, garlic have a stronger scent than apple. The stronger scent motivate us to eat different types of foods.

ii) How many food materials you have identified correctly?
Answer:
Seven.

iii) Write a few lines on the relation between smell and taste.
Answer:

1. Taste and smell are intimately entwined. This close relationship is most apparent in how we perceive the flavour of food.
2. Taste itself is focussed on distinguishing chemicals that have sweet, salty, sour, bitter or umami taste.
3. However interactions between the senses of taste and smell enhance our perceptions of the foods, we eat.

iv) Have you ever felt that a particular food is tasty just by looking at it?
Answer:
I felt so many times. In general, we prefer the food material, which is attractive to our eyes and flavour to nose, then we taste it.

Activity – 4
What is the role of different parts of the mouth in helping us to taste keeping sugar crystals over the tongue?

1. Place some sugar crystals on the tongue and keep mouth opened and see that your tongue dosen’t touch the palate.
2. Record the time from the moment you placed the crystals on your tongue till you got the taste by using stop watch.
3. Now repeat the test by placing the sugar crystals on the tongue and pressing it against the palate.
4. Record the time from placing sugar crystals to getting the taste. Or put a drop of sugar solution on your tongue using a dropper.

Observation :
Based on the above activity we know that taste can be identified easily when the tongue is pressed against the palate.
i) Can we taste on dry tongue?
Answer:
No. We can’t taste on dry tongue.

ii) Which way helped you taste faster? Why?
Answer:
Taste can be identified faster when the tongue is pressed against the palate.
When the tongue is pressed against the palate the food substance is pressed against the opening of the taste bud letting it reach taste celjs triggering taste signals. Finally the taste is recognised in the brain.

Activity – 5
How do you show that the breakdown of food by using the model of chalk piece kept in vinegar?

1. Break a piece of chalk into two halves.
2. Crush one half to tiny pieces leaving the other as it is.
3. Take two small mineral wafer bottles QA ltr bottle) cut them into two equal halves and discard the upper portion.
4. Now we have two beakers from the lower cut portion.
5. Fill them half with vinegar and add the crushed chalk to one beaker and the other uncrushed half chalk to the other.
6. Observe them after half-an-hour or so.

i) Which one dissolved faster the crushed chalk or the whole one?
Answer:
Beaker with crushed chalk dissolved faster than the whole one.
This experiment tells us the need of mechanical crushing of food the mouth to increase surface area for action of substances that aid in digestion.

ii) How does this process of mechanical crushing go on in the mouth?
Answer:
Mechanical crushing of food goes in the mouth by chewing.

iii) Which parts in the mouth are involved in this?
Answer:
Teeth and tongue.

iv) What are the systems involved in this process?
Answer:
Digestive system, Nervous system, Muscular system.

Activity – 6
Observe the diagram and answer the questions and fill the table.
i) Observe the model or chart of jaw, on the basis of the figure try to guess what are the functions molars could be?
Answer:
Chewing and grinding.

ii) What do you think could be the function of inscisors?
Answer:
The function of inscisors is biting the food.

iii) Which set of teeth helps in grinding food?
Answer:
Premolars and molars.

iv) Which set helps in tearing food?
Answer:
Canines help in tearing food.

v) What is your dental formula?
Answer:
is the dental formula.

Table

Name of teeth	Number	Shape	Function
Incisors	8	Chisel, sharp edges	Biting
Canines	4	Sharp, pointed edges	Tearing
Premolars	8	Diamond shape blunt and flat	Chewing and grinding
Molars	12	Rectangular, blunt and flat	Chewing and grinding

Activity – 7
Testing pH of mouth at intervals of one hour.

1. Collect a strip of pH paper with a colour chart from a chemistry teacher.
2. Take a small piece of the pH paper and touch it to your tongue.
3. Match the colour with the colour chart and note the pH.
4. Take some readings after having your food at lunch break.
5. Compare your readings with that of your friend.
6. Take at least 4 readings.

Table

S.No.	Name of the Student	pH value before lunch	pH value after lunch	pH value after an hour	pH value after 2 hrs
1.	Sagar	7.4	6.8	7.0	7.4
2.	San jay	7.4	6.8	7.0	7.4
3.	Raju	7.1	6.9	7.0	7.1
4.	Krishna	7.3	6.8	7.0	7.3
5.	Kiran	7.4	6.8	7.0	7.4
6.	Yadav	7.2	6.7	7.0	7.2

i) What is the usual range of pH of your mouth Acidic (or) Basic
Answer:
The usual range of pH of our mouth is more or less 6.5. At low level the saliva is acidic and at high level it is basic.

ii) Did you observe any change in pH after eating? What may have caused the change?
Answer:
Yes, 1 observed the change in pH. Bicarbonates in saliva changed that into basic.

iii) In what kind of pH do you think salivary amylase acts well?
Answer:
In the pH range 7.2 to 7.4 it acts well in alkaline medium.

iv) Does this type of food have any role to play on the pH of our mouth?
Answer:
If the food that enters is acidic it will be converted into basic stuff and then it is swallowed.
Based on the above tests we know that salival secreted causes the medium to change to alkaline as it aids in action salivary amylase.

Activity – 8
Making a model of oesophagus to observe how bolus moves forward.

1. Take a piece of waste cycle tube and insert one or two potatoes into it.
2. Lubricate the inner side of the tube with oil.
3. In the same way smear oil over potatoes.
4. Insert oil coated potatoes in the tube.
5. Now try to push the potatoes by squeezing the tube.

i) How do you squeeze the tube to make the potatoes pass through?
Answer:
By pushing the potato from behind.

ii) Do you think that the muscles in the wall of the oesophagus have to do something like this?
Answer:
Yes.

iii) How did oil help you in pushing the potatoes through the pipe?
Answer:
Oil acted as a lubricant to push the potato easily in the forward direction.

Activity – 9
How is the stomach protected from the secretions of its own acids?

1. Take two similar green leaves.
2. Grease one leaf with petroleum jelly, leave the other free.
3. Add 1 or 2 drops of some weak acids on both the leaves.
4. Observe them after half-an-hour or so and write your observations.

i) Which leaf was effected by the acid?
Answer:
The leaf to which petroleum jelly was not applied.

ii) What kind of change did you observe in the leaves?
Answer:
The colour of the leaf changes.

iii) What saved the other leaf from the effect of acid?
Answer:
Petroleum jelly.
From the above activity we can conclude that mucus secreted by the walls of stomach protects stomach from the harmful effects of hydrochloric acid.

Activity – 10
Paper tube and folded papers.

1. Provide students with a piece of paper.
2. Let them calculate the area of one side of the paper and make a roll of it.
3. Try to fill the tube by inserting few folded papers as much as possible in it.
4. Pull out the papers from the tube, unfold them and find out the whole area of the papers.

i) Compare the area of the folded papers with that of the roll. Do you find any increase in the area ? If so try to find out the reasons?
Answer:
Area is increased. The space inside the folded papers is very much high. So we can insert as many folded papers as we could.
From the above activity we can infer that the inner surface of the small intestine contains thousands of finger-like projections called villi which increase the surface area of absorption of nutrients in small intestine.