AP SSC 10th Class Biology Solutions Chapter 2 Respiration – The Energy Releasing System

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 2 Respiration – The Energy Releasing System Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 2nd Lesson Respiration – The Energy Releasing System

10th Class Biology 2nd Lesson Respiration – The Energy Releasing System Textbook Questions and Answers

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Question 1.
Distinguish between
(a) Inspiration and Expiration
(b) Aerobic and Anaerobic respiration
(c) Respiration and Combustion
(d) Photosynthesis and Respiration
Answer:
(a) Inspiration and Expiration:

Inspiration Expiration
1. It is also called inhalation. 1. It is also called exhalation.
2. The air or water is taken into the respiratory organ. 2. The air or water is sent out of the respiratory organ.
3. It is an active process. 3. It is a passive process.
4. Rib cage moves forward and outward. 4. Rib cage moves downward and inward.
5. Diaphragm contracts and becomes flattened. 5. Diaphragm relaxes and becomes original dome shaped.
6. Increase in volume of thoracic cavity. 6. Decrease in volume of thoracic cavity.
7. Air pressure in lungs is less than the atmospheric pressure. 7. Air pressure in lungs is greater than the atmospheric pressure.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

(b) Aerobic respiration and Anaerobic respiration:
(OR)
Respiration is energy-producing process in the organisms. It takes place both in the presence and absence of oxygen. Laxmi said there are some differences between the two processes. How do you support her?
Answer:

Aerobic respiration Anaerobic respiration
1. It takes place in the presence of oxygen. 1. It takes place in the absence of oxygen.
2. In aerobic respiration, complete oxidation of glucose takes place. 2. In anaerobic respiration, the glucose molecule is incompletely oxidised.
3. End products are CO2 and water. 3. End products are either ethyl alcohol or lactic acid and CO2.
4. Lot of energy is liberated (38 ATP). 4. Relatively small energy is liberated (2 ATP).
5. It occurs in plant’s and animal’s cells. 5. Occurs in many anaerobic bacteria and human muscle cells.
6.
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 1		 6.
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 2
7. It has two stages – Glycolysis and Krebs cycle. 7. It has two stages – Glycolysis and Fermentation.

(c) Respiration and Combustion:
(OR)
Even though both are oxidation processes, combustion and respiration are different in many aspects. Explain those differences.
(OR)
Combustion and respiration are oxidative processes but still there are differences between them. What are they?
(OR)
Write the differences between respiration and combustion.
Answer:

Respiration Combustion
1. It occurs in living cells. 1. It is non – cellular.
2. Oxidation of food materials especially glucose to carbon dioxide and water is called respiration. 2. When sugar burns CO2 and water are produced and energy is released as heat. This process is called combustion.
3. Oxidation of sugar molecules occurs at the body temperature of an organism. 3. Heat is to be supplied for the sugar molecule to burn.
4. The energy is released in several stages. 4. The energy is released at once as heat.
5. Several intermediate substances are formed. 5. No intermediate substances are formed.
6. Enzymes are required for oxidation. 6. Enzymes are not required for combustion.
7. Respiration occurs in the presence of water. 7. Combustion occurs in the absence of water.
8. It is a controlled process. 8. It is an uncontrolled process.
9. Energy is stored in ATP in the body. 9. Energy is not stored and is released into the atmosphere.

(d) Photosynthesis and Respiration:

Photosynthesis Respiration
1. Occurs only in all plants and photo­synthetic bacteria. 1. Occurs in all living organisms.
2. Takes place in the presence of sunlight. 2. Takes place throughout day and night.
3. A plant can survive without performing photosynthesis for few days. 3. No organism can survive without respiration for few minutes even.
4. In plants, only few cells perform photosynthesis. 4. All living cells in an organism perform this process.
5. Raw materials are C02 and water. 5. Uses carbohydrates and oxygen.
6. Oxygen is liberated. 6. Carbon dioxide is released.
7. It occurs in chloroplast. 7. It takes place in cytoplasm and mitochondria.
8. Adds weight to the organism. 8. Decrease weight of the organism.
9. It is an anabolic process. 9. It is a catabolic process.
10.
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 3		 10.
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 4

Question 2.
State two similarities between aerobic and anaerobic respiration.
Answer:
Similarities between aerobic and anaerobic respiration:

  1. Both are catabolic processes.
  2. Both aerobic and anaerobic respiration takes place in all cells.
  3. Energy is released in both the processes.
  4. CO2 is the end product of both processes.
  5. First stage of both respiration is glycolysis.
  6. Respiratory substances in both processes are glucose, fatty acids and amino acids.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 3.
Food sometimes enters the wind pipe and causes choking. How does it happen?
Answer:

  1. Pharynx is the common passage of both air and food.
  2. From here air enters into trachea and food enters into oesophagus.
  3. Pharynx is connected to larynx through glottis a slit like opening.
  4. A cartilagenous flap called EPIGLOTTIS act as a lid over glottis and prevents food from entering into trachea during swallowing.
  5. Any food particles enters the trachea it causes chocking.
  6. Sometimes the food particles are forced back by cough.

Question 4.
Why does the rate of breathing increase while walking uphill at a normal pace in the mountains? Give two reasons.
Answer:
The rate of breathing increases while walking uphill at a normal pace in the mountains.

  1. It is because as we go up the hill above sea level the concentration of oxygen is greatly reduced. So we have to breathe more to get required amount of oxygen.
  2. While walking uphill a lot of oxygen is used by our body to release energy from glucose.
  3. This leads to lack of oxygen in the cells.
  4. We take in oxygen when we breathe.
  5. Hence to increase the amount of oxygen intake there is an increase in breathing rate during walking uphill.

Question 5.
Air leaves the tiny sacs in the lungs to pass into capillaries. What modification is needed in the statement?
Answer:

  1. Gaseous exchange takes place within the lungs by diffusion from the alveoli to blood capillaries and vice versa.
  2. The carbondioxide in the blood is exchanged for oxygen in alveoli.
  3. This sentence may be modified as “Air that contains oxygen reaches the tiny sacs in the lungs to pass into capillaries.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 6.
Plants photosynthesize during daytime and respire during the night. Do you agree to this statement? Why? Why not?
Answer:

  1. No, I do not agree with this statement. Plants photosynthesize during daytime only and respire during the daytime as well as night time also.
  2. During daytime when photosynthesis occurs in the presence of sunlight. Oxygen is produced. The leaves use some of this oxygen for respiration and the rest diffuses into air.
  3. During daytime CO2 produced by respiration is all used up in photosynthesis by leaves.
  4. At night time no photosynthesis occurs and oxygen diffuses into leaves to carryout respiration.

Question 7.
Why does a deep sea diver carry oxygen cylinder on his/her back?
Answer:

  1. When we go deep into the sea, the oxygen level decreases. Oxygen is in dissolved state in water.
  2. Humans are adapted for utilizing oxygen in gaseous state. They cannot use dissolved oxygen for breathing.
  3. Only aquatic animals like fish can utilize the dissolved oxygen for breathing using gills.
  4. Human beings have lungs for respiration. Therefore, sea divers have to carry oxygen cylinders in their back so as to receive oxygen.
  5. If they do not carry them, they do not get oxygen and there is a chance even to die.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 8.
How are alveoli designed to maximise the exchange of gases?
Answer:
The human lungs have been designed to maximise the exchange of gases as follows.

  1. The interior of lung is divided into millions of small chambers called alveoli.
  2. The presence of millions of alveoli in the lungs provide a very large surface area.
  3. If all alveoli of our lungs are spread out they will cover an area of nearly 160 m2.
  4. Availability of large surface area maximises the exchange of gases.

Question 9.
Where will the release of energy from the glucose in respiration take place? Mala writes lungs, while Jiya writes muscles. Who is correct and why?
Answer:

  1. Respiration is the process of releasing energy from the breakdown of glucose.
  2. Respiration takes place in every living cell, all the time.
  3. All cells need to respire in order to produce the energy that they require.
  4. During respiration the release of energy from the glucose takes place in muscles but not in lungs.
  5. So Jiya is correct. The energy is released from the muscle cells during respiration. Only gaseous exchange takes place in lungs.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 10.
What is the role of epiglottis and diaphragm in respiration?
Answer:
Epiglottis:

  1. Epiglottis, a flap like muscular valve controls movement of air and food towards their respective passages.
  2. Epiglottis is partly closed when we swallow food and it opens more widely when we take a breath and air enters the lungs.
  3. Epiglottis allows air pass through the larynx and the respiratory system.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 6

Diaphragm :

  1. The diaphragm in the respiratory system is the dome shaped sheet of muscle that separates the chest from the abdomen.
  2. When the diaphragm contracts during inhalation it flattens out a bit. This results in the enlargement of the volume of the chest cavity.
  3. This reduces the pressure in the lungs and air enters into lungs from outside the body.
  4. During exhalation, the diaphragm relaxes and assumes its dome shape. This change increases the pressure on the lungs and squeezes the air through the nose to the atmosphere.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 7

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 11.
How does gaseous exchange take place at blood level?
Answer:

  1. Lungs are made up of several thousands of small chambers called alveoli.
  2. Within the alveoli, exchange of gases take place between the gases inside the alveoli and blood.
  3. Blood arriving in the alveoli has higher CO2 concentration which is produced during respiration by the body cells.
  4. At the same time air in the alveoli has a much lower concentration of CO2 and this allows the diffusion of CO2 out of the blood and to alveolar air.
  5. Similarly blood arriving in the alveoli has a lower oxygen concentration while air in the alveoli has a higher oxygen concentration.
  6. Therefore oxygen moves into the blood by diffusion.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 8

Question 12.
Explain the mechanism of gaseous exchange at bronchiole level.
Answer:

  1. the trachea (wind pipe) is divided into two tubes called BRONCHI. As there are two lungs each bronchus (singular) enters the lungs on the same side.
  2. In the lung, the bronchus divides into smaller and smaller branches called BRONCHIOLES which enters into each alveoli.
  3. When oxygen from outside reaches the alveoli through bronchioles and the carbondioxide from alveoli moves out.
  4. The inhaled air from outside enters into bronchioles through nostrils → nasal cavities → pharynx → larynx → trachea → bronchus.
  5. The exhaled air from alveoli enters bronchioles → pharynx → nasal cavities → nostrils → outside.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 9

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 13.
After a vigorous exercise or work we feel pain in muscles. What is the relationship between pain and respiration?
Answer:

  1. We obtain energy by oxidation of glucose molecule.
  2. In the absence of oxygen (anaerobic respiration) glucose is converted to latic acid.
  3. During vigorous exercise oxygen gets used up faster in the muscle cells that can be supplied by blood.
  4. When oxygen supply is inadequate the muscles use energy released during the anaerobic breakdown of glucose.
  5. The anaerobic respiration by muscles bring about partial breakdown of glucose to form lactic acid.
  6. The accumulation of lactic acid in the muscles causes muscular pains or cramps.

Question 14.
Raju said, “Stems also respire along with leaves in plants”. Can you support this statement? Give your reasons.
Answer:
Yes. I support the statement of Raju that stems also respire along with leaves in plants.
The reasons are

  1. The stems of herbaceous plants have stomata.
  2. So the exchange of respiratory gases in the stems of herbaceous plants takes place through stomata.
  3. The oxygen from air diffuses into the stem through stomata and reaches all the cells for respiration.
  4. The carbon dioxide released during respiration diffuses out into the air through the stomata.
  5. In woody stems the bark has lenticels for gaseous exchange. Through lenticels, oxygen diffuses in and carbon dioxide diffuses out into the air.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 10

Question 15.
What happens if diaphragm is not there in the body?
Answer:

  1. The lungs cannot draw in air or push it out by themselves. The chest wall muscles and the diaphragm helps the lungs in moving air into and out of them.
  2. If diaphragm is not there in the body, we would not be able to breathe.
  3. The diaphragm is the major muscle in the process of respiration.
  4. It separates the thoracic and abdominal cavities.
  5. In the absence of diaphragm, the relaxation and contraction of the chest wall muscles do not take place and thereby inspiration and expiration become difficult that leads to death of the person.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 16.
If you have a chance to meet pulmonologist, what questions are you going to ask about pulmonary respiration?
Answer:
If I have a chance to meet pulmonologist, I would like to ask the following questions:

  1. What is pulmonary respiration?
  2. What is the organ involved in pulmonary respiration?
  3. What is the name of blood vessel that brings deoxygenated blood to lungs?
  4. What is the name of the blood vessel that carries oxygenated blood from the lungs to the heart?
  5. Out of the two lungs which one is larger than the other?
  6. What type of diagnostic test will be performed to assess the function of lungs?
  7. What is pulmonary edema? How does it occur?
  8. Can all the diseases of the lungs be cured permanently?

Question 17.
What procedure do you follow to understand anaerobic respiration in your school laboratory?
(OR) (Lab Activity)
Write the procedure and observations of the experiment which you have conducted in your laboratory to prove that CO2 and heat are evolved during anaerobic respiration by using yeast.
(OR)
How do you prove that carbon dioxide is released during anaerobic respiration?
(OR)
How do yeast cells convert glucose solution to CO2 and ethyl alcohol?
Answer:
Aim : To prove that CO2 is released during anaerobic respiration.
Apparatus: Thermos flask, splitted corks, thermometer, wash bottle, glass tubes, liquid
paraffin, glucose solution, yeast cells, bicarbonate solution.
Procedure:

  1. Remove dissolved oxygen from glucose solution by boiling it for a minute and then cooling it without shaking.
  2. Now add some yeast to the glucose solution and fix a two-holed rubber stopper to the flask.
  3. The supply of oxygen from the air can be cut off by pouring a 1cm layer of liquid paraffin into the mixture through the holes.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 11
  4. Insert one end of the thermometer into the thermos flask. See the mercury bulb of thermometer keep inside the solution.
  5. Arrange for any gas produced by the yeast to escape through a wash bottle containing bicarbonate solution or lime water as shown in the figure.
  6. Add a few drops of diazine green (Janus Green B) solution to the yeast suspension before you pour liquid paraffin over it.
  7. The blue diazine green solution turns pink when oxygen is in short supply around it.
  8. Warm the apparatus to about 37° F in order to speed up the test.
  9. Keep the apparatus undisturbed for one or two days.

Observations :

  1. After two days it can be observed that lime-water of the wash bottle turns into milky white precipitate.
  2. Increase in temperature in thermometer.
  3. Alcohol smell given off from the flask.

Result: These observations indicate that yeast cells respire anaerobically converting glucose solution into CO2, ethyl alcohol and release heat energy.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 18.
What are your observations in the combustion of sugar activity?
Answer:
Observations in the combustion of sugar:

  1. When sugar is heated, first it melts, chars and later burns producing flames.
  2. When sugar is combusted, carbon dioxide and water are produced.
  3. Energy is also released in the form of heat and it released at once.
  4. We cannot control the combustion of sugar.
  5. Intermediate products are not formed.
  6. We can combust sugar in the absence of water and enzymes.
  7. When combustion of sugar, heat energy is released into the atmosphere and we cannot store it for further use.

Question 19.
Collect information about cutaneous respiration in frog. Prepare a note and display them in your classroom.
(OR)
How does frog respire with the help of skin?
Answer:

  1. Respiration through skin is called cutaneous respiration.
  2. In frog, skin is an additional or secondary or accessory respiratory organ.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 12
  3. Skin is a very important respiratory organ in both on land and water.
  4. One-third of the total oxygen taken up by frog is through the skin.
  5. Frog also keeps its skin moist. Frog skin has a large number of mucous glands which secrete mucous onto the surface of the skin.
  6. The mucous layer retains water and reduces evaporation of water from body.
  7. To keep the skin wet and moist frogs jump into water very frequently.
  8. Frog skin is supplied with a large number of blood vessels which help in absorbing oxygen from the water.
  9. The carbon dioxide produced during to respiration, diffuses out into the water through the blood vessels present in the skin of the frog.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 20.
Collect information about respiratory diseases (because of pollution, tobacco) .and discuss with your classmates.
Answer:
Respiratory diseases because of pollution:

  1. Irritation of eyes, nose, mouth and throat.
  2. Headaches and dizziness.
  3. Respiratory symptoms such as coughing and running nose.
  4. Respiratory and lung diseases including
    a) Asthma attacks
    b) Chronic obstructive pulmonary disease (COPD)
    c) Reduced lung function
    d) Pulmonary cancer caused by a series of carcinogen chemicals that through inhalation
    e) Mesothelioma: A particular type of lung cancer, usually associated with expo¬sure to asbestos (it usually occurs 20 – 30 years after the initial exposure)
    f) Pneumonia: Infection of lungs caused by bacteria.
    g) Bronchitis: It is inflammation or swelling of bronchial tubes.
    h) Emphysema: It is a lung condition in which tiny air sacs in lungs alveoli fill up with water.

Respiratory diseases due to tobacco :

  1. Chronic bronchitis: A long term inflammation of the bronchi is characterized by coughing.
  2. Lung cancer: An abnormal continuous multiplication of cells that can result in tumors in the lining of the bronchi.
  3. Emphysema: A chronic lung condition that affects the air sacs in the lungs characterized by shortness of breath, coughing, fatigue, sleep and heart problems.

Question 21.
What is the pathway taken by air in the respiratory system? Illustrate with a labelled diagram.
Answer:
The path way taken by air in the respiratory system:
Nostrils → Nasal cavity → Pharynx → Larynx → Trachea → Bronchus → Bronchioles → Alveolus → Blood.

  1. Nostrils : Air enters the body through the nostrils.
  2. Nasal cavity: Air is filtered and its temperature is also brought close to that of the body.
  3. Pharynx: It is the junction of respiratory and digestive system. Epiglottis – a flap like muscular valve controls movement of air and food towards their respective passages.
  4. Larynx: Also called voice box. This stiff box contains vocal cords. When air passes out of the lungs and over vocal cords, it causes them to vibrate. This produces sounds on the basis of our speech, song etc.
  5. Trachea: This is also called wind pipe. It channels air to lungs.
  6. Bronchi: Trachea at it’s lower end divides into two bronchi one leading to each lung.
  7. Bronchioles: The bronchi further divided into smaller and smaller branches called bronchioles.
  8. Alveoli: Clusters of air sacs called alveoli in the lungs which are very small and numerous. The gaseous exchange takes place here as blood capillaries take up oxygen and expel CO2.
  9. Blood: It carries oxygen, to each and every cell of the body and collects CO2 from them.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 13

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 22.
Draw a block diagram showing events in respiration. Write what you understood about cellular respiration.
Answer:
Events in respiration :
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 14AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 15

Cellular respiration :

  1. All living cells must carry out cellular respiration.
  2. Oxidation of glucose of fatty acids releasing energy takes place in cells, hence it is called cellular respiration.
  3. It can be in the presence of oxygen that is aerobic respiration or in its absence that is anaerobic respiration (fermentation).
  4. Cellular respiration in prokaryotic cells like that of bacteria occurs within the cytoplasm.
  5. In Eukaryotic cells cytoplasm and mitochondria are the site of cellular respiration.
  6. The energy released in cellular respiration is stored in a special compound called ATP.
  7. ATP is utilised for carrying out other functions in the cell.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 23.
How do you appreciate the mechanism of respiration in our body?
Answer:

  1. Respiration is essential for life because it provides energy for carrying out all the life processes which are necessary to keep the organism alive.
  2. The energy that is obtained from respiration is used to build the organism by way of cell growth, reproduction and cell repair, etc.
  3. All systems in living beings need energy to survive.
  4. Respiration helps to expel out the toxic carbon dioxide out of the cells. This CO2 will be utilised by the plants to produce food materials through the process of photosynthesis.
  5. The respiratory system goes into operation from the movement of our birth and works without ever stopping as long as we live our breath continues.
  6. During exhalation, the vocal cords in the larynx vibrate to produce sounds and help in speaking as we like.

Question 24.
Prepare an article on anaerobic respiration to present school symposium.
Answer:
Anaerobic respiration :

  1. Respiration that occurs without oxygen is known as anaerobic respiration.
  2. It is present in primitive organisms and muscular cells in higher animals.
  3. Alcohol, CO2 and H2O are end products in this process.
  4. AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 5

Merits:

  1. In the absence of oxygen it is good process.
  2. Mechanism is simple.
  3. Suitable to microorganisms

Demerits:

  1. Provides less energy
  2. Not suitable to higher animals

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 25.
Prepare a cartoon on discussion between haemoglobin and chlorophyll about respiration.
Answer:
Discussion between haemoglobin and chlorophyll about respiration:
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 16

Haemoglobin: Hello good morning chlorophyll. How are you?

Chlorophyll: Very good morning haemoglobin. I am fine.

Haemoglobin: I am also doing well. Let me know something about you.

Chlorophyll: I am a green coloured pigment present in leaves of plants.

Haemoglobin: How many types of chlorophylls are there ?

Chlorophyll: We are four types i.e., chlorophyll – a, chlorophyll – b, chlorophyll – c and chlorophyll – d.

Haemoglobin: May I know your job in leaves?

Chlorophyll: Yes. Why not? I am an essential factor required to prepare food through the process of photosynthesis in plants.

Haemoglobin: Oh! You are participating in the process of preparing food materials by green plants.

Chlorophyll: Now tell me about your presence.

Haemoglobin: I am present only in animal cells. That too in the red blood cells of the blood. The red colour of the blood is due to my presence.

Chlorophyll: Then tell me about your function in respiration?

Haemoglobin: During respiration, I carry oxygen to the cells in the body tissues.

Chlorophyll: How are you able to do this?

Haemoglobin: I have an oxygen binding element iron. It binds oxygen on four corners of it. I form oxy-haemoglobin with oxygen in the lungs.

Chlorophyll: What happens to the digested food in the cells?

Haemoglobin: In cells, oxygen breakdown the glucose molecule into C02 and H20 releasing large amount of energy. Around 38 ATP molecules are produced.

Chlorophyll: What is the use of this energy?

Haemoglobin: This energy is utilised by the cell to carry other functions.

Chlorophyll: Thank you haemoglobin. You have taught me everything about respiration. In our next meeting we will discuss another topic.

Haemoglobin: Thank you chlorophyll for your interest and patience.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Fill in the blanks.

  1. Exhaled air contains ———– and ———–.
  2. A flap like muscular valve controls movement of air and food is ———–.
  3. Energy currency of the cell is called ———–.
  4. Lenticels are the respiratory organs that exist in ———– part of the plant.
  5. Mangrove trees respire with their ———–.

Answer:

  1. carbon dioxide, water vapour
  2. Epiglottis
  3. ATP (Adenosine Tri Phosphate)
  4. stem
  5. aerial roots

Choose the correct answer.

6. We will find vocal cords in [ ]
A) Larynx
B) Pharynx
C) Nasal cavity
D) Trachea
Answer: A

7. Cluster of air sacs in lungs are called [ ]
A) Alveoli
B) Bronchi
Answer: A

8. Which of the following is correct ? [ ]
i) The diaphragm contracts – volume of chest cavity increased
ii) The diaphragm contracts – volume of chest cavity decreased
iii) The diaphragm expands – volume of chest cavity increased
iv) The diaphragm expands – volume of chest cavity decreased
A) i B) i and ii C) ii and iii D) iv
Answer: A

9. Respiration is a catabolic process because of [ ]
A) Breakdown of complex food molecules
B) Conversion of light energy
C) Synthesis of chemical energy
D) Energy storage
Answer: A

10. Energy is stored in [ ]
A) Nucleus
B) Mitochondria
C) Ribosomes
D) Cell wall
Answer: B

10th Class Biology 2nd Lesson Respiration – The Energy Releasing System

Activity – 1

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

How do you test the presence of water vapour and heat in the exhaled air?
Answer:

  1. Keep your palm around an inch away from your nose.
  2. Feel you breathing out.
  3. Do not remove your palm until you have finished the activity.
  4. Breathe steadily for 1 – 2 minutes.
  5. Now take a piece of any fruit.
  6. Chew and before swallowing it keep the fingers of the other palm on your neck, now swallow it.

Questions:

  1. What did you notice? What happens to your breath as you try to swallow?
    Answer:
    We cannot swallow while breathing. We usually stop breathing when we swallow food.
  2. What is helping you to swallow without deflecting it to the windpipe?
    Answer:
    Epiglottis is helping me to swallow without deflecting food to the windpipe.

Activity – 2
Write an experiment to observe changes during combustion of sugar.
(OR)
What are your observations in combustion of sugar activity.
Answer:
Aim: To observe changes during combustion of sugar.
Apparatus: Wooden stand, test tubes, rubber stopper, delivery tube, glucose or sucrose powder, lime water, spirit lamp.
Procedure:

  1. Take a small amount of glucose in a small test tube.
  2. Arrange the apparatus as shown in the figure.
  3. Heat the test tube until the glucose catches fire.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 17

Observations :

  1. In the initial stage the glucose becomes liquid.
  2. Later it turns to black colour after catching fire.
  3. In this process carbon dioxide and water are produced.
  4. Energy is released as heat.
  5. The carbon dioxide released changes lime water to milky white.

Conclusion:

  1. From this experiment, we can conclude that carbon dioxide, water and heat are produced during combustion of glucose in the laboratory.
  2. The carbon dioxide changes lime water to milky white in nature.

Activity – 3

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

How can you prove that carbon dioxide is evolved during respiration?
(OR)
Write the experimental procedure and draw the arrangement of apparatus to show that CO2 is evoloved in respiration.
To understand that CO2 is evolved during respiration, what experiment you have performed in your laboratory? Explain the procedure.
(OR)
Write an experiment to prove that CO2 is released during respiration.
Answer:
Aim: To prove that CO2 is released during aerobic respiration.
Apparatus: Two wide mouthed plastic or glass bottles, germinating seeds, dry seeds, two small injection bottles or beakers with lime water.

  1. Take two wide mouthed glass bottles.
  2. Keep germinating bengal gram seeds in one bottle and dry seeds in another bottle.
  3. Keep two small beakers with lime water in each glass bottles.
  4. Close the glass bottles tightly.
  5. Keep both the sets undisturbed for one or two days.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 18

Observation:

  1. After two days it can be observed that lime water of the beaker placed in the bottle containing germinating seeds turns into milky white.
  2. And the lime water kept in the glass bottle containing dry seeds do not change its colour.
    Result: It indicates that germinating seeds liberated carbon dioxide which turns lime
    water into milky white.

Activity – 4

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Explain the procedure you have adopted in your school to prove that heat is liberated during respiration. What result we will get, if you perform this experiment with dry seeds?
(OR)
Write the procedure you have followed to observe “heat is evolved during respiration” in your laboratory. What precautions did you take during the activity?
Answer:
Aim: To prove that heat is liberated during respiration.
Apparatus: Two Thermos flasks, two thermometers, two rubber corks, dry seeds, germinating seeds.
Procedure:

  1. Take a handful of moong or bazra seeds.
  2. Soak the seeds in water a day before experiment.
  3. Keep these soaked seeds in a cloth pouch and tie with a string tightly.
  4. Next day collect the sprouts / germinated seeds from the pouch in a thermos flask and take dry seeds in another thermos flask.
  5. Remove the lid and prepare a cork through which you can bore a hole to insert thermometers into two flasks in such a way that the bulb of the thermometer should dip into the germinating and dry seeds.
  6. Close the thermos flasks with tight fitting rubber corks.
  7. Record the initial temperature in both the flasks and record it for every two hours for at least 24 hours.
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 19

Observation: Constant increase in the temperature is observed in thermometer placed in the germinating seeds.
Result: Hence it is proved that germinated seeds respire and liberate heat which is responsible for increase in the temperature.
Questions:

  1. Make a graph by using your observations.
    Answer:
    AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 20
  2. Is there any increase in temperature?
    Answer:
    Yes, there is increase in temperature.
  3. Does the temperature increase steadily or does it abruptly increase at a time of the day?
    Answer:
    The temperature in the thermometer increases steadily.
  4. Where does the heat come from?
    Answer:
    The sprouting or germinating seeds respire and liberate heat.

10th Class Biology 2nd Lesson Respiration – The Energy Releasing System InText Questions and Answers

10th Class Biology Textbook Page No. 25

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 1.
Can it be said that Priestly’s experiment helped us to find out more about composition of air? How?
Answer:
Yes, Priestly’s experiments helped to find out the composition of air when burning of charcoal, carbon dioxide is produced which is the one of the composition of air done by Lavoisier.
Another experiment with phosphorus done by Lavoisier was cleared that a gas which is the respirable air that is helped in burning was oxygen also a component of air.
Lavoisier proved experimentally that carbon dioxide and oxygen were the components of air. Lavoisier confirmed the experiments of Priestly about the gases present in the air.

Question 2.
What gas was produced by combustion according to Lavoisier?
Answer:
The gas produced by combustion is carbon dioxide.

Question 3.
What did Lavoisier find out about air from his experiments?
Answer:
A fixed air carbon dioxide and respirable air oxygen which helped in burning were liberated during his experiments.

Question 4.
What conclusion can be drawn from Lavoisier’s experiments?
A. Oxygen and carbon dioxide are the compositions of air.

10th Class Biology Textbook Page No. 26

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 5.
Which gas do you think is Lavoisier talking about when he says chalky acid gas?
Answer:
Carbon dioxide.

Question 6.
Which gas according to Lavoisier is respirable air?
Answer:
Oxygen.

Question 7.
What steps in the process of respiration does Lavoisier mention as an inference of his experiments?
Answer:
Lavoisier mentioned that there were two steps in the respiration.
1. Inspiration: Breathing oxygen.
2. Expiration: Eliminating carbon dioxide from lungs.

Question 8.
It is a common observation that our breath is warmer than the air around us ; does respiration have anything to do with this?
Answer:
Our exhaled air is warmer than the air around us because heat is liberated during respiration.

10th Class Biology Textbook Page No. 27

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 9.
What does this experiment indicate?
Answer:
This experiment indicates that carbon dioxide is liberated during respiration.

Question 10.
Which gas turns lime water milky?
Answer:
Carbon dioxide.

Question 11.
Which gas do you think might be present in greater quantities in the air we breathe out as compared to air around us?
Answer:
Nitrogen (78%) is present in greater quantities in the air.

Question 12.
We are also aware of the fact that water vapour deposits on a mirror if we breathe out on it; where does this water vapour come from in Exhaled air?
Answer:
Water vapour is liberated during respiration.

10th Class Biology Textbook Page No. 29

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 13.
Why are we advised not to talk while eating food?
Answer:

  1. When we are eating food, epiglottis helps to avoid food entering into trachea.
  2. If we talk while we eat food, there is a chance of food entering into trachea and causes choking.
  3. As a result irritation and inflammation takes place in the respiratory tract.
  4. So we are advised not to talk while eating.

10th Class Biology Textbook Page No. 30

Question 14.
What is the role of diaphragm and ribs in respiration? Are both active in man and woman?
Answer:

  1. Diaphragm and ribs are helpful the chest cavity to increase or decrease the volume for inspiration and expiration in respiration.
  2. Diaphragm plays a major role in men and ribs play a major role in mechanism of respiration.

10th Class Biology Textbook Page No. 31

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 15.
What can be concluded from this?
Answer:
All movements of breathing is controlled by nerves leading from the brain.

Question 16.
What happens during the process of breathing?
Answer:
During the process of breathing, the patterns of breathing show a great range for they are coordinated with moment by moment needs of the body for supply of oxygen and removal of carbon dioxide.

Question 17.
Which gas needs to be removed from our body during exhalation? Where does the extra amount of gas come from?
Answer:
Carbon dioxide needs to be removed during exhalation. The extra amount of gas comes from the breakdown of glucose to release energy in the mitochondria. Carbon dioxide gas is released here.

Question 18.
What is the composition of inhaled air?
Answer:
Inhaled air contains oxygen -21%, C09 – 0.03%, Nitrogen – 78%.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 19.
When exhaled air is compared with inhaled air, is there any difference in composition?
Answer:
Yes, there is a difference between inhaled air and exhaled air.
The difference is
AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System 21

10th Class Biology Textbook Page No. 32

Question 20.
Why does the amount of oxygen vary between exhaled and inhaled air?
Answer:
Because some amount of oxygen will be utilised during cellular respiration in the body. Hence the difference in amount of oxygen occurs.

Question 21.
What has raised the percentage of carbon dioxide in exhaled air?
Answer:
CO2 is released from all the cells in the body in respiration and is added to the exhaled air.

10th Class Biology Textbook Page No. 34

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 22.
Do cells of alveoli or lungs also require oxygen to carry out cellular respiration? Why / Why not?
Answer:

  1. Alveoli are made of squamous epithelium tissue which is very thin and elastic
  2. Alveoli are so thin that oxygen can pass from air-filled alveoli to R.B.C inside the vessels.
  3. Simple squamous epithelial cells function as mediators of filtration and diffusion. As these cells are living tissue they also need oxygen.
  4. This is done through the exchange of gases in the alveoli.

Question 23.
After undergoing strenuous exercise we feel pain in muscles, does adequate oxygen reach the muscles?
Answer:
No. Adequate oxygen does not reach the muscles.

Question 24.
What is being formed in the muscles?
Answer:
Lactic acid.

10th Class Biology Textbook Page No. 42

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 25.
In which set does the colour change faster? Why?
Answer:
In the set which has germinating seeds the colour changes faster. Because CO2 is formed faster in aerobic respiration.

Think and Discuss

10th Class Biology Textbook Page No. 29

Question 1.
What will happen if the respiratory tract is not 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 create 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 of the body.
  5. Hence respiratory tract should be moist for smooth exchange of gases.

Question 2.
Are both lungs similar in size?
Answer:
No. Right lung is slightly bigger than left lung.

AP SSC 10th Class Biology Solutions Chapter 2 Respiration - The Energy Releasing System

Question 3.
Why are alveoli so small and uncountable in number?
Answer:

  1. The pouch-like air sacs at the ends of the smallest bronchioles 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.

 

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

AP State Board Syllabus AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Biology Solutions 1st Lesson Nutrition – Food Supplying System

10th Class Biology 1st Lesson Nutrition – Food Supplying System Textbook Questions and Answers

Improve your learning

Question 1.
Write differences between
(a) Autotrophic nutrition – Heterotrophic nutrition:
Answer:

Autotrophic nutrition Heterotrophic nutrition
1. Organism makes its own food. 1. Organism can not makes its own food.
2. Food is prepared from C02, water and sunlight. 2) Food is prepared from other organism.
3. Chlorophyll is required. 3. Chlorophyll is not required.
4. It takes place during day time. 4. It takes place throughout the day.
5. Examples are all green plants and photosynthetic bacteria. 5. All animals, Fungi and some bacteria.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

(b) Ingestion – Digestion :
Answer:

Ingestion Digestion
1. Taking in of food into the body through mouth is called ingestion. 1. Breaking up of complex molecules of food into simple and small molecules is called digestion.
2. Ingestion does not change the chemical and mechanical structure of food. 2. Digestion changes the chemical and mechanical structure of food.

(c) Light reaction – Dark reaction :
(OR)
Differentiate the reactions that take place in presence of light and the reactions which do not require light in photosynthesis.
Answer:

Light reaction Dark reaction
1. It occurs in the grana of the chloroplast. 1. It 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. It occurs in the grana of the chloroplast. 3. It occurs in the stroma of the chloroplast.
4. Light reaction absorbs oxygen and light energy. 4. Dark reaction absorbs only CO2
5. End products are O2, ATP and NADPH. 5. End product is Glucose.
6. Photolysis of water occurs. 6. Carbon fixation occurs.
7. First stage of photosynthesis. 7. Second stage o: photosynthesis.

(d) Chlorophyll – Chloroplast:
Answer:

Chlorophyll Chloroplast
1. Chlorophyll is the green coloured pigment present in the chloroplast. 1. It is the green coloured plastid enclosed by membranes.
2. It contains one atom of magnesium. 2. It consists of 3 membranes.
3. It harvests solar energy and convert into chemical energy. 3. It is responsible for enzymatic reactions leading to the synthesis of glucose.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 2.
Give reasons.
a) Why photosynthesis is considered as the basic energy source for most of living world?
(OR)
Why can we say that photosynthesis is the basic energy source for the living world?
Answer:

  1. All living organisms constantly need energy to be alive.
  2. They get energy from the food they eat.
  3. The food directly or indirectly comes from the green plants through photosynthesis.
  4. Hence photosynthesis can be considered as the basic energy source for most of living world.

b) Why is it better to call the dark phase of photosynthesis as a light independent phase?
Answer:

  1. The term dark reaction or light independent does not mean that they occur when it is dark at night.
  2. It only means that the reactions are not depend on light.
  3. Hence we call the dark phase of photosynthesis as a light independent phase.

c) Why is it necessary to destarch a plant before performing any experiment on photosynthesis?
Answer:
1) To get better results, it is necessary to destarch a plant before performing any experiment on photosynthesis.
2) Because if starch is present it may interfere with the result of the experiment.

d) Why is it not possible to demonstrate respiration in green plants kept in sunlight?
Answer:

  1. We cannot demonstrate an experiment of respiration in green plants kept in sunlight.
  2. Because if sunlight is present, the C02 produced in respiration will be used in photosynthesis.
  3. So we must conduct an experiment on respiration in green plants in a dark room.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 3.
Give examples.
a) Digestive enzymes
Answer:
The digestive enzymes are:

  1. Salivary Amylase (Ptyalin),
  2. Pepsin,
  3. Trypsin,
  4. Lipase,
  5. Peptidases,
  6. Sucrase,
  7. Amylase (Pancreatic juice)

b) Organisms having heterotrophic nutrition is seen in organisms like:
Answer:
Heterotrophic nutrition is seen in organisms like:

  1. All animals and human beings.
  2. Some protozoans Ex: Amoeba.
  3. Some parasitic plants Ex: Cuscuta
  4. Saprophytes Ex: Bread moulds, yeast, mushrooms, etc.

c) Vitamins
Answer:
Water soluble vitamins:
B complex (B1) Thiamine, (B2) Riboflavin, (B3) Niacin, (B6) Pyridoxine,
(B12) Cyanocobalamine, Folic acid, Pantothenic acid, Biotin, (C) Ascorbic Acid.
Fat soluble: (A) Retinol, (D) Calciferol, (E) Tocoferol, (K) Phylloquinine.

d) Nutritional deficiency diseases
Answer:
Eg: Kwashiorkor, Marasmus etc.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 4.
Where do plants get each of the raw materials required for photosynthesis?
Answer:

Raw materials Sources
External factors:
1. Carbondioxide		 Atmosphere
2. Sunlight Sun
Internal factors:
3. Water		 Ground water
4. Chlorophyll and enzymes Present in leaf.

Question 5.
Explain the necessary conditions for autotrophic nutrition and what are its by products.
Answer:
A. Necessary conditions:

  1. Autotrophic nutrition takes place through the process of photosynthesis.
  2. Carbon dioxide, water, chlorophyll pigment and sunlight are the necessary conditions required for autotrophic nutrition.
  3. The rate of photosynthesis depends on availability of sunlight.

B. By products:

  1. Photosynthesis is the main process for autotrophic nutrition.
  2. Carbohydrates and oxygen are the by products of photosynthesis.

Question 6.
With the help of chemical equation explain the process of photosynthesis In detail with the help of a flow chart.
Answer:
Process of photosynthesis:

  1. The chemical equation representing the process of photosynthesis is
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 1
  2. Definition: Photosynthesis is a photochemical reaction during carbohydrates are formed using carbon dioxide and water in the chloroplasts of the green plants in the presence of sunlight.
  3. CO2 water, sunlight and chlorophyll are the requirements of photosynthesis.
  4. Glucose, O and water are the end products of the reaction.
  5. Photosynthesis have two phases.
    1) Light reaction 2) Dark reaction
  6. Light reaction have three steps, i) Oxidation of chlorophyll ii) Photolysis iii) Formation of ATP, NADPH and O2
  7. In dark reaction CO2 is utilized and finally glucose is formed which is converted and stored as starch.

FLOW CHART:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 2

Question 7.
Name the three end products of photosynthesis.
Answer:
Glucose, oxygen and water are the three end products of photosynthesis.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 8.
What is the connecting substance between light reaction and dark reaction?
Answer:
The hydrogen of NADPH present in the stroma is the connecting substance between light reaction and dark reaction.

Question 9.
Most leaves have the upper surface is more green and shiny than the lower ones. Why?
(OR)
In most of leaves the upper surface will be more green and shiny than the lower surface. Why?
Answer:

  1. The upper surface comprising of the palisade parenchyma.
  2. The lower surface comprising of the spongy parenchyma.
  3. Palisade parenchyma contains more number of chloroplasts than the spongy parenchyma.
  4. Thus the upper surface is more green and shiny than the lower ones.

Question 10.
Explain the structure of chloroplast with a neatly labelled sketch.
(OR)
Explain the structure of a chloroplast with the help of a rough diagram.
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 3

  1. Chloroplast is a membranous structure consisting of 3 membranes.
  2. The third layer forms stacked sac like structures called granum.
  3. The intermediatery fluid filled colourless portion is called stroma.
  4. It is responsible for enzymatic reaction leading to the synthesis of glucose in plants.
  5. Substances found in chloroplast, capture sunlight are called photosynthetic pigments.
  6. Chlorophyll pigment contain one atom of magnesium.
  7. Two major kinds of chlorophylls are associated with thyakoid membranes.
  8. Chlorophyll-a is blue-green in colour and chlorophyll-b is yellow-green colour.
  9.  Around 250-400 pigments molecules are grouped as light harvesting complex units in granum.
  10. Some of the events occur in chloroplast are :
    a) Conversion of light energy to chemical energy.
    b) Splitting of water molecule.
    c) Reduction of carbondioxide to carbohydrates.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 11.
What is the role of acid in stomach?
Answer:

  1. The internal walls of stomach has number of gastric glands. They secret gastric juice.
  2. It contains HCl and enzymes.
  3. HCl kills the bacteria present in the food and protects us from their harmful effects.
  4. And also denatures the proteins so that enzymes can act easily on them.

Question 12.
What is the function of digestive enzyme?
Answer:

  1. The function of digestive enzyme is to increase the process of breaking up of complex molecules into simpler and absorb molecules.
  2. This makes easy for the body to absorb food.

Question 13.
How is the small intestine designed to absorb digested food? Explain.
(OR)
How is food absorbed by villi in small intestine?
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 4
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 5

  1. Small intestine is the largest part in digestive system.
  2. Absorption is its main function including last stage of digestion.
  3. The inner surface of small intestine has millions of tiny finger-like projections called villi.
  4. Due to the presence of villi, the absorbing surface area of small intestine increases.
  5. And the large surface area of small intestine helps in the rapid absorption of digested food.
  6. The digested food which is absorbed through the walls of the small intestine goes into our blood.
  7. Long and folding structure increase the ability of small intestine.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 14.
How are fats digested in our bodies? Where does this process take place?
What is emulsification? How it helps in digestion of fats? (OR)
How are fats digested? Where do they get digested?
Answer:

  1. Bile juice and lipase enzymes helps in fat digestion.
  2. Bile juice is secreted by liver.
  3. Fats are digested by converting them into small globules like forms by the help of the bile juice.
  4. This process is called emulsification.
  5. Lipase enzyme is secreted by pancreas.
  6. It converts emulsified fats into fatty acids and glycerol.
  7. AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 6
  8. This process takes place in duodenum and small intestine.

Question 15.
What is the role of saliva in the digestion of food ?
(OR)
How does saliva digest food ?
Answer:

  1. Saliva is secreted by three pairs of salivary glands present in the mouth.
  2. Human saliva contains an enzyme called amylase (ptyalin).
  3. It converts starch into maltose (a sugar).
  4. The food is mixed thoroughly with saliva and becomes wet and slippery.
  5. Saliva helps in the smooth passage of food in the food pipe.

Question 16.
What will happen to protein digestion as the medium of intestine is gradually rendered alkaline ?
Answer:

  1. The food coming from the stomach to intestine is acidic in nature.
  2. Bile and pancreatic juices render the internal condition of the intestine gradually to a basic or alkaline one.
  3. Protein digestion continues even if the medium of intestine is gradually changed to alkaline.
  4. In the alkaline medium pancreatic enzyme trypsin can act on the food and digests the proteins.
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 7
  5. The enzymes present in the intestinal juice like peptidases complete the digestion of proteins into amino acids.
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 8

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 17.
What is the role of roughages in the alimentary tract?
Answer:

  1. Roughages are the fibres of either carbohydrates or proteins.
  2. Plenty of roughages in the diet avoid constipation.
  3. Roughages help in the easy movement of faeces in the large intestine.
  4. They help in the easy digestion of food and keep the alimentary canal clean and healthy.

Question 18.
What is malnutrition? Explain some nutrition deficiency diseases.
Answer:
Malnutrition: Eating of food that does not have one or more than one nutrients in required amount is known as malnutrition.
Malnutrition is of three types:

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

Nutrition deficiency diseases:

  1. Kwashiorkor disease: This is due to protein deficiency in diet.
    Symptoms:
    i) Body parts becomes swollen due to accumulation of water in the intercellular spaces,
    ii) Very poor muscle development,
    iii) Swollen legs,
    iv) Fluffy face,
    v) difficult to eat,
    vi) diarrhoea,
    vii) Dry skin.
  2. Marasmus: This is due to deficiency of both protein and calories. Generally this disease occurs when there is an immediate pregnancy or repeated child births.
    Symptoms:
    i) Lean and weak,
    ii) Swelling in joints of limbs,
    iii) Less developed muscles,
    iv) Dry skin,
    v) diarrhoea.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 19.
How do non-green plants such as fungi and bacteria obtain their nourishment?
Answer:

  1. Bacteria and fungi are non-green plants. So they cannot prepare their own food materials.
  2. They are saprophytes which feed on dead and decaying plant and animal bodies.
  3. The fungi and bacteria breakdown the complex organic molecules present in dead and decaying matter by releasing chemical substances into simple substances out¬side the body.
  4. These simpler substances are then absorbed by fungi and bacteria as their food.

Question 20.
If we keep on increasing CO2 concentration in the air, what will be the rate of photosynthesis?
Answer:

  1. If the CO2 concentration in the air increases, the rate of photosynthesis also increases.
  2. If the CO2 concentration raises above 5% then the rate of photosynthesis reduces.
  3. At certain CO2 concentration the rate of photosynthesis is constant.
  4. Here a rise in CO2 levels has no affect on the rate of photosynthesis as the other factors such as light intensity become limited.

Question 21.
What happens to plant if the rate of respiration becomes more than the rate of photosynthesis ?
Answer:

  1. Respiration is a catabolic (destructive) process and photosynthesis is an anabolic (constructive) process.
  2. If the rate of respiration becomes more than the rate of photosynthesis, the amount of food oxidised will be more than the food produced.
  3. This affects the growth and development of plants and may even results in the death of the plant.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 22.
Why do you think that carbohydrates are not digested in the stomach?
(OR)
Where are carbohydrates digested in alimentary canal?
Answer:

  1. For the digestion of carbohydrates enzyme ptyalin or amylase are required.
  2. The gastric juice produced by stomach do not contain the enzyme ptyalin or amylase, it contains only pepsin which digests proteins.
  3. Hence carbohydrates are not digested in the stomach.
  4. Carbohydrates are partially digested in the mouth and completely in small intestine.

Question 23.
What process do you follow in your laboratory to study the presence of starch in leaves?
(OR)
(Activity – 1)
How do you test the presence of starch in leaves ? (OR)
Mention the materials required and explain the experiment to prove the presence of starch in leaves. What inference do you draw from this experiment?
Answer:
Aim: To study the presence of starch in leaves.
Apparatus: Beaker, test tube, bunsen burner, tripod stand, asbestos gauze, ethanol, leaf, petridish, iodine solution.
Procedure:

  1. Select a leaf of a potted plant with soft thin leaves.
  2. Boil the leaf in methylated spirit over a water bath till it becomes pale white due to the removal of chlorophyll.
  3. Observe the leaf.
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 10
  4. Spread the leaf in a dish and add a few drops of tincture iodine / betadine solution on it. Again observe the leaf.

Observation: The presence of starch will be indicated by a blue-black colour in leaf. Result: The experiment proves that starch is present in leaves. It is formed by Photo-synthesis.
Precautions:

  1. Do not boil the methylated spirit test tube directly on flame.
  2. Boil the water bath with low flame.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 24.
How would you demonstrate that green plants release oxygen when exposed to light? (OR) (Lab Activity)
Write the experimental procedure to prove that oxygen is produced during photosynthesis in the presence of light. (OR)
What materials are required to prove that oxygen is produced during photosynthesis in the presence of light? What procedure we need to follow to perform the above experiment?
We have conducted experiment that prove the release of oxygen when photosynthesis happens?
i) What are the plants used for this experiment? Where do they grow?
ii) How did you conduct the above experiment? In which context large number of air bubbles released? Do you noticed?
Answer:
i) Hydrilla plants are used for this experiment they grow in water.
ii) Experiment to demonstrate the release of oxygen during photosynthesis.
Aim: To prove that oxygen is produced during photosynthesis by hydrilla funnel experiment.
Apparatus: Beaker with water, test tube, funnel, hydrilla twigs, glowing splinter.
Procedure:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 11

  1. Arrange the apparatus as shown in the figure.
  2. Place some water plant hydrilla in a beaker containing pond water, and cover these by a short stemmed funnel.
  3. Invert a test – tube full of water over the stem of the funnel.
  4. Ensure that the level of water in the beaker is above the level of stem of the inverted funnel.
  5. Place the apparatus in the sun for at least 2 or 3 hours.
  6. After sometime it is observed that gas bubbles come from the hydrilla plant. These bubbles are collected at the end of the test tube pushing the water into the beaker.
  7. After sufficient gas is collected test – tube is taken out of the beaker carefully by closing it with thumb.

Observation: Test the gas in the test – tube by inserting a glowing incense stick which would burst into flames. This shows the presence of oxygen.
Result: This shows that oxygen is produced during photosynthesis.
Precautions:

  1. Funnel should be smaller than the beaker.
  2. Necessary care is to be taken while removing the test tube from the stem of the funnel.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 25.
Collect information from your primary health centre of malnutrition child at various ages and make a table your own and display in the classroom.
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 12Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 13

Question 26.
If there were no green plants, all life on the earth would come to an end ! Comment.
(OR)
The survival of organisms would become difficult, if there are no green plants on the earth. How do you support?
Answer:

  1. Plants play the most important part in the cycle of nature.
  2. Without plants there could be no life on earth.
  3. Plants are the only organisms that can make their own food and all other living beings directly or indirectly depend on plants for their food.
  4. Moreover plants release oxygen into the atmosphere through photosynthesis.
  5. Oxygen is essential for the organisms to respire.
  6. Hence without green plants, all life on the earth would come to an end.

Question 27.
Draw a neat labelled diagram of chloroplast found in leaf, and its role in photosynthesis.
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 14Role of Chloroplast in photosynthesis:

  1. Chloroplasts trap solar energy.
  2. They convert that solar energy into chemical energy.
  3. They help in the formation of glucose.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 28.
Draw the label diagram of human digestive system. List out the parts where peristalsis takes place.
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 15Parts where peristalsis takes place: Oesophagus, stomach, small intestine and large intestine.

Question 29.
Raheem prepared a model showing the passage of the food through different parts of the alimentary canal. Observe this and label its parts.
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 16Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 17

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 30.
Observe the following diagram and write a note on light dependent, light independent reactions.
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 18Answer:
Note on light dependent reactions:

  1. Light dependent reactions are also called as photochemical phase.
  2. The light dependent reaction takes place in chlorophyll containing thylakoids called grana of chloroplasts.
  3. Several steps occur in the light dependent reaction.
  4. Step – 1: The chlorophyll on exposure to light energy becomes activated by absorbing photons.
  5. Step – II: The energy is used in splitting the water molecule into two component ions named hydrogen (H+), hydroxyl ion (OH–). This reaction is known as photolysis.
  6. Step – III: OH– ions through a series of steps produce water (H2O) and O2.
  7. The end products of light reaction are ATP, NADPH and O2.

Note on dark reaction or light independent reaction:

  1. In light independent phase the hydrogen of the NADPH is used to combine it with CO2, by utilizing ATP energy and to produce glucose.
  2. This synthesis occurs in a number of steps using certain special intermediate compounds (mainly RUBP – Ribulose hi phosphate) and enzymes. Finally glucose is converted to starch.
  3. All these reactions occur in the stroma region of the chloroplast.

Question 31.
Almost all the living world depends on plants for food material. How do you appreciate the process of making food by the green plants?
(OR)
What facts about the green plants do you appreciate?
Answer:
Leaf is a wonderful machine to synthesize food:

  1. The leaf is the important site of photosynthesis and is called as food factory of the plant.
  2. This plant organ can be treated as a wonderful natural machine which converts solar energy into useful chemical energy.
  3. With all his scientific knowledge and technical skills, man has not produced anything similar leaf for utilization of solar energy without polluting the atmosphere.
  4. This machine provides food and supports the life by providing oxygen for all the organisms including man on this planet.
  5. Nature has given us such a wonderful machine free !!

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 32.
Even a hard solid food also becomes smooth slurry in the digestive system by the enzymes released at a particular time. This mechanism is an amazing fact. Prepare a cartoon on it.
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 19

Question 33.
What are good food habits?
Answer:
The food habits I am going to follow after reading this chapter are:

  1. I take balanced diet which contains proper amounts of carbohydrates, proteins, fats, vitamins and minerals.
  2. I avoid taking food containing high proportion of fat.
  3. I eat food as much required by my body. I do not over eat.
  4. I will not eat rich meals over several days.
  5. I eat simple balanced meals, eat it leisurely and thoroughly masticating the food.
  6. I avoid doing violent exercise soon after eating food.
  7. I empty the bowels regularly avoiding constipation.
  8. I will see to have plenty of roughages in the diet.

(OR)
After reading the chapter nutrition, I would like to follow the following food habits.

  1. Having simple, well balanced meals.
  2. Eating them in a leisurely manner.
  3. Thoroughly masticating the food.
  4. Avoiding strenuous exercise soon after eating food.
  5. Drinking plenty of water and having regular bowel movement.
  6. Decreasing consumption of coffee or tea per day.
  7. Taking leafy vegetables at least 3 times a week and taking of fruits and vegetables plenty.
  8. Maintaining regular timings for daily food consumption.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Fill in the blanks.

  1. The food synthesized by the plant is stored as ———–.
  2. ———– are the sites of photosynthesis.
  3. Pancreatic juice contains enzymes for carrying the process of digestion of ———– and ———–.
  4. The finger-like projections which increases the surface area in small intestine are called ———–.
  5. The gastric juice contains ———– acid.
  6. ———– vitamin is synthesized by bacteria present in intestine.

Answer:

  1. carbohydrates
  2. Chloroplasts
  3. proteins, fats
  4. Villi
  5. HCl
  6. Cyanocobalamin

Choose the correct answer.

  1. Which of the following plant take the food by parasitic nutrition? [ ]
    A) Yeast
    B) Mushrooms
    C) Cuscuta
    D) Leeches
    Answer: C & D
  2. The rate of photosynthesis is not affected by [ ]
    A) Light intensity
    B) Humidity
    C) Temperature
    D) Carbon dioxide concentration
    Answer: B
  3. A plant is kept in dark cupboard for about forty eight hours before conducting any experiment on photosynthesis in order to [ ]
    A) Remove chlorophyll from leaves
    B) Remove starch from leaves
    C) Ensure that no photosynthesis occurred
    D) Ensure that leaves are free from the starch
    Answer: B
  4. The digestive juice without enzyme is [ ]
    A) Bile
    B) Gastric juice
    C) Pancreatic juice
    D) Saliva
    Answer: A
  5. In single-celled animals, the food is taken by [ ]
    A) the entire body surface
    B) mouth
    C) teeth
    D) vacuoles
    Answer: A
  6. Which part of the plant takes in carbon dioxide from the air for photosynthesis? [ ]
    A) Root hair
    B) Stomata
    C) Leaf veins
    D) Sepals
    Answer: B

10th Class Biology 1st Lesson Nutrition – Food Supplying System Activities

Activity – 1

How do you prove experimentally that carbon dioxide is necessary for photosynthesis by Mohl’s half leaf experiment?
(OR)
List out the materials required and the procedure to be followed to prove that ‘carbon dioxide’ is essential for photosynthesis.
(OR)
You know that the factors like CO2, Light and Chlorophyll are essential for photosynthesis. Write any one of experiment related to the factors essential for photosynthesis.
Answer:
Aim:
To prove-that carbon dioxide is essential for photosynthesis by Mohl’s half leaf experiment.
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 20Apparatus:
Wide mouthed transparent bottle, KOH solution, potted plant, vertically split cork, Iodine solution.
Procedure:
Arrange the apparatus as shown in the figure.

  1. Take a healthy potted plant and keep it in the dark for nearly a week for the removal of starch from the leaves.
  2. A wide mouthed transparent bottle is taken.
  3. Put potassium hydroxide pellets or potassium hydroxide solution (KOH) in the bottle.
  4. This KOH absorbs CO2 present in the bottle.
  5. Insert splitted cork in the mouth of the bottle.
  6. Insert one of the leaves of destarched plant through a split cork into transparent bottle.
  7. Arrange half of the leaf is inside bottle and the remaining half outside.
  8. Leave the plant in the sunlight for 2-3 hours.
  9. After a few hours, test this leaf and other leaf of this plant for starch.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Observation :

  1. The part of the leaf outside the bottle turns blue-black because starch is formed in this part due to photosynthesis.
  2. The part of the leaf inside the bottle does not turn blue-black because the carbon dioxide present inside the bottle is absorbed by potassium hydroxide solution.
  3. All the other factors water, sunlight and chlorophyll are available but not CO2. Hence starch is not formed in the leaf part which is inside the bottle.

Result: This experiment proves that CO2 is necessary for photosynthesis. Precautions:

  1. The part of the leaf kept inside the bottle should not touch potassium hydroxide solution.
  2. The apparatus should be kept air tight by applying grease or vaseline.

Activity – 2

Sunlight is necessary to form starch in green leaves.
(OR)
Write the materials required and the procedure to prove that light is essential for Photosynthesis.
(OR)
Write the procedure, precautions and observations in the lab activity, “Sunlight is necessary for photosynthesis”.
Answer:
Aim:
To prove that light is necessary for photosynthesis to form starch.
Apparatus:
Potted plant, light screen, iodine solution.

  1. Keep potted plant in dark for one week to remove starch.
  2. Take one black paper and cut it with your own design.
  3. Keep design paper properly on the both sides with the help of clips.
  4. Ensure that light does not pass through the covered area with black paper.
  5. Keep the arranged apparatus at sunlight available area.
  6. After few hours of exposure to bright sunlight detach the leaf.
  7. Boil the leaf in methylated spirit over water bath. It becomes pale white due to the removal of chlorophyll. Take the leaf from test tube and spread the leaf in a petridish.
  8. Add few drops of Iodine on leaf. The parts of the leaf, which could get light through the cut out design, turns blue-black colour.
  9. The parts of the leaf which could not get light are not turned into blue – black colour.
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 21

Observation:
It is observed that only the parts of the leaf, which could get light through the cut out design, turn blue black, showing the presence of starch.

Result:
This experiment proves that light is necessary to form starch in the process of photosynthesis.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Activity – 3

Demonstrate litmus paper test on salivary amylase in the mouth.
Answer:

  1. Before taking food into the mouth, take a litmus indicator paper and touch it to the tongue.
  2. We observe no colour change in litmus paper.
  3. Perform the litmus test again after chewing the food and swallowing it.
  4. The red litmus paper turns to blue colour.
  5. The blue litmus paper do not turns to red colour.
  6. This demonstrates that amylase converts complex carbohydrates to simple sugar.
  7. Amylase is alkaline in nature. This turns litmus paper blue when touches glucose at the second time.
    AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 22

Activity – 4

Observe different digestive enzymes and their role in digesting food in a tabular form.
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 23

10th Class Biology 1st Lesson Nutrition – Food Supplying System InText Questions and Answers

10th Class Biology Textbook Page No. 2

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 1.
Can you think of some raw materials needed for photosynthesis?
Answer:
Yes. Photosynthesis needs the following raw materials.

  1. Sunlight, CO2 water are external factors.
  2. Chlorophyll and enzymes are internal factors.

Question 2.
What could be the end products of the process of photosynthesis?
Answer:
Glucose, water and oxygen are the end products of photosynthesis.

10th Class Biology Textbook Page No. 4

Question 3.
Do you think solar energy transforms into chemical energy by the process of photosynthesis?
Answer:
Yes, solar energy transforms into chemical energy by the process of photosynthesis.

Question 4.
What are the materials that you think would be essential for the synthesis of carbohydrates in the process of photosynthesis?
Answer:
The materials essential for the synthesis of carbohydrates in the process of photosynthesis are carbon dioxide, water, sunlight and chlorophyll.

Question 5.
Do you think the equation tells us about all the materials involved?
Answer:
Yes, the materials which are essential for photosynthesis and the products formed are involved in the equation.

10th Class Biology Textbook Page No. 5

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 6.
What had Priestly done to introduce the mint plant without disturbing the experimental setup?
Answer:
AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System 24Priestly should have tilted the bell jar to one side and introduced the mint plant without disturbing the experimental set up.

Question 7.
How did Priestly light the candle from outside?
Answer:
Priestly might have used convex lens through which beam of sun rays can light the candle from outside or he might have used long burning stick, to light the candle by lifting the jar partially.

Question 8.
Do you find any relationship between candle, rat, mint plant? Discuss.
Answer:
Priestly’s experiment confirmed that gaseous exchange was going on and plants were giving out a gas that supported burning and was essential for the survival of animals.
By combustion process candle releases carbondioxide. By respiration process rat also releases carbondioxide. During photosynthesis process mint plant uses this carbondioxide and releases oxygen. This oxygen will be used by rat to stay alive and for the candle to burn.
So there is a relationship between respiration and photosynthesis by candle, rat and mint plant.

10th Class Biology Textbook Page No. 6

Question 9.
Why was the plant kept in dark and then in sunlight?
Answer:

  1. The plant is kept in the dark for nearly a week to remove the starch from the leaves.
  2. Then only we can understand that the starch is formed in the leaves or not after the experiment when the plant is kept in the sunlight.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 10.
Why did we study two leaves in the Mohl’s half leaf experiment?
Answer:

  1. To test CO2 is essential or not for photosynthesis, two leaves are used in the experiment.
  2. One leaf with the plant and another one used in the experiment.
  3. The leaf which is exposed to the atmospheric air becomes bluish-black. It proves that starch is prepared in the leaf by using CO2 from atmosphere.
  4. The leaf inside the flask containing potassium hydroxide, which absorbs CO2 present in the bottle does not become bluish black. It shows that CO2 is necessary for photosynthesis.

10th Class Biology Textbook Page No. 7

Question 11.
What precautions do you need while removing test tube from the beaker? Discuss with your teacher.
Answer:

  1. When sufficient gas is collected lift the test tube carefully from the beaker by closing its mouth with the thumb.
  2. Because of that the gas present in the test tube cannot escape into the atmosphere.

10th Class Biology Textbook Page No. 8

Question 12.
Which part of leaf turns blue black? What about the remaining part?
Answer:

  1. The part of the leaf, which could get light through the cut design turns to blue black showing the presence of starch.
  2. The remaining part of the leaf which did not get light, do not turn blue, indicating that starch is not prepared.

Question 13.
Observe the colour of the leaf stained with iodine. Can you tell why it is stained differently?
Answer:

  1. Some parts of the leaf prepared starch.
  2. Some parts of the leaf does not prepared starch.
  3. So it is stained differently.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 14.
What about plants having coloured leaves?
Answer:
Plants having coloured leaves also carry out photosynthesis. The coloured leaves containing pigments pass on the energy of sunlight trapped by them to chlorophyll.

Question 15.
How is that new leaves which look dark red in colour in several plants turn green?
Answer:

  1. The new leaves which look dark red in colour contain coloured chromoplasts.
  2. As the leaf grows the chromoplasts turns to chloroplasts and the leaf appears green in colour.

Question 16.
Do plants having reddish or yellowish leaves also carry out photosynthesis?
Answer:

  1. Yes. Plants having reddish or yellowish leaves also carry out photosynthesis.
  2. The pigments present in reddish or yellowish leaves pass on the energy of sunlight trapped by them to chlorophyll.

Question 17.
What made plants carry out photosynthesis while even green coloured animals (like some birds) could not?
Answer:

  1. Chlorophyll and other pigment molecules trap (harvest) solar energy, convert it into chemical energy in the thylakoid membranes of the chloroplast.
  2. But animals having green colour on their body cannot trap solar energy and cannot perform photosynthesis. Photosynthesis is possible only in plants but not in animals.

10th Class Biology Textbook Page No. 9

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 18.
Where is chlorophyll and other pigments present in the plant?
Answer:
Chlorophyll and other pigments are present in the grana thylakoids of chloroplast in leaf.

Question 19.
Do you think the new reddish leaves of plants also carry out photosynthesis? What could be the role of their colour?
Answer:

  1. Yes. New reddish leaves of plants also carry out photosynthesis.
  2. Chromoplasts are responsible for the reddish colour of leaves.
  3. They also pass on the energy of sunlight which they trap to the photosystems.

10th Class Biology Textbook Page No. 10

Question 20.
What makes chloroplast appear completely different from other cell organelles?
Answer:

  1. Substances found in chloroplast, which capture sunlight are called photosynthetic pigments.
  2. Two major kinds of chlorophyll are associated with thylakoid membranes.
  3. Chlorophyll – a (blue – green in colour) and chlorophyll – b (yellow – green); around 250 to 400 pigment molecules are grouped as light harvesting units in each granum.
  4. Such innumerable units in chloroplasts make them appear completely different from other organelles.

10th Class Biology Textbook Page No. 13

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 21.
What happens to the food once it enters our body?
Answer:

  1. The food once enters our body it gets digested by various enzymes in different parts of alimentary canal.
  2. Digestion starts in the mouth and it completes in the small intestine.
  3. Finally it absorbed in the small intestine into the circulatory system.

10th Class Biology Textbook Page No. 15

Question 22.
Name the enzymes which act on carbohydrates.
Answer:
Ptyalin (salivary amylase), amylase and sucrose are the enzymes that act on carbohydrates.

10th Class Biology Textbook Page No. 16

Question 23.
What are the end products of fats?
Answer:
The end products of fats are fatty acids and glycerol.

Question 24.
What are the enzymes that act on proteins?
Answer:
Pepsin, Trypsin and Peptidases are the enzymes that act on proteins.

Question 25.
Which digestive juice contains no enzymes?
Answer:
Bile juice produced by liver contains no enzymes.

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 26.
What do you think about the process of digestion?
Answer:

  1. The process of digestion occurs in the alimentary canal or digestive system.
  2. During the process of digestion large complex macro molecules present in the food are converted to simple and small molecules.
  3. Digestion provides the food material properly absorbed by the body.

Question 27.
What are the major steps of digestion?
Answer:
The major steps of digestion are

  1. Ingestion
  2. Digestion
  3. Absorption and
  4. Defecation.

10th Class Biology Textbook Page No. 18

AP SSC 10th Class Biology Solutions Chapter 1 Nutrition – Food Supplying System

Question 28.
Collect information about pellagra and discuss with your teacher.
Answer:

  1. Pellagra is a vitamin-deficient disease.
  2. Niacin (Vitamin – B3) is essential for the metabolism of carbohydrates, proteins and fats.
  3. The resources for vitamin – B3 are kidney, liver, meat, egg, fish, oil seeds and legumes.
  4. Deficiency of niacin results in a disease called PELLAGRA.

Symptoms: Pellagra is described by 3 Ds – Diarrhoea, Dermatitis, Dementia.
A more comprehensive list of symptoms include

  1. Sensitivity to sunlight
  2. Aggression
  3. Dermatitis
  4. Alopecia (hair loss)
  5. Edema (swelling)

Smooth, beefy red, glossitis, red skin lesions, insomnia (sleepless), weakness, mental confusion, nerve damage are the symptoms of this pellagra.

Prevention: By taking of yeast, meat, fish, milk, eggs, green vegetables, beans and cereal grains, we can prevent this disease.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

AP State Board Syllabus AP SSC 10th Class Physics Solutions Chapter 1 Heat Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Physics Solutions 1st Lesson Heat

10th Class Physics 1st Lesson Heat Textbook Questions and Answers

Improve your learning

Question 1.
What would be the final temperature of a mixture of 50 g of water at 20° C temperature and 50 g of water at 40° C temperature? (AS1)
Answer:
In CGS system :
Mass m1 = 50 g
Higher temperature = T1 = 40° C
Mass m2 = 50 g
Lower temperature = T2 = 20° C
AP SSC 10th Class Physics Solutions Chapter 1 Heat 1

Question 2.
Explain, why dogs pant during hot summer days using the concept of evaporation. (AS1)
(OR)
How do dogs cool their body? Explain by using the process of evaporation.
Answer:

  • Dogs pant during hot summer days and get their body cooled. This cooling effect is due to evaporation.
  • Evaporation is a surface phenomenon. Temperature of a system falls during evaporation.
  • During summer the temperature in the human body increases.
  • The temperature of the skin becomes higher and the water in the sweat glands starts evaporating. Since evaporation is a cooling process human body becomes cool.
  • Dogs don’t have sweat glands. Their body is covered with hair. They have sweat glands only in their feet.
  • So by panting the water on the tongue undergoes evaporation resulting in the cooling of the dog’s body.

Question 3.
Why do we get dew on the surface of a cold soft drink bottle kept in open air? (AS1)
(OR)
Raju observed small droplets of water outside a cold soft drink bottle kept in open air. What is the reason for the formation of droplets?
Answer:

  • When cold soft drink bottle is kept in open air, the temperature of surrounding air is higher than the temperature of cold drink bottle.
  • Air contains molecules in the form of vapour.
  • During the motion of water molecules in air strike the surface of cold drink bottle.
  • Then the molecules of air lose their kinetic energy which leads to lower the temperature and they convert into droplets.
  • So dew is formed on the surface of cold soft drink bottle.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 4.
Write the differences between evaporation and boiling. (AS1)
(OR)
Sita observed decrease in quantity of spirit kept in a vessel placed in open air. Whereas Ramu observed formation of bubbles on a water surface when it is heated. What are those two processes? Distinguish between those two processes.
Answer:

Evaporation Boiling
1. The process of escaping of molecules from the surface of a liquid at any temperature is called evaporation. 1. The process in which the liquid phase changes to gaseous phase at constant temperature. This temperature is called boiling point of liquid.
2. Evaporation takes place at any temperature. 2. Boiling takes place at a definite temperature.
3. The temperature of liquid gets down. 3. The temperature of liquids increases up to a constant temperature.
4. The kinetic energy does not change. 4. The kinetic energy of the molecules increases with the increase of temperature.
5. The evaporation depends on surface area, wind, speed, humidity. 5. The boiling depends on atmospheric pressure.
6. It is surface phenomenon. 6. It is bulk phenomenon.
7. Eg : 1) Wet clothes dries.
2) Sea water evaporates to form clouds.		 7. Eg : 1) Water boils at 100° C.

Question 5.
Does the surrounding air become warm or cool when vapour phase of H2O condenses? Explain. (AS1)
Answer:

  • Gases have more higher energy than liquids and solids.
  • When vapour condenses, it changes from gas to liquid.
  • Therefore there is a drop in energy.
  • This energy has to go (somewhere) to the surroundings.
  • So surrounding air becomes warm when vapour phase of H20 condenses.

Question 6.
Answer these. (AS1)
a) How much energy is transferred when 1 gm of boiling water at 100°C condenses to water at 100°C?
Answer:
CGS system :
Mass of water = m = 1 gm
Latent heat of vapourisation = 540 cal/gm.
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100°C
Q = mLvapour = 1 × 540 = 540 cal.

(OR)

In SI system :
Mass of water = m = 1 gm = 1 × 10-3 kg
Latent heat of vapourisation = 540 cal/gm.
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100°C
Q = mLvapour – 1 × 540 = 540 cal.
In SI, Q = 540 × 4.18 = 2257 J.

b) How much energy is transferred when 1 gm of boiling water at 100° C cools to water 0° C?
Answer:
CGS system :
Latent heat of vapourisation = 540 cal/gm
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100 °C. m = 1 gm.
Q1 = mLvapour = 1 × 540 = 540 cal.
The specific heat of water = 1 cal/gm-°C
Difference in temperature = 100-0 = 100°C.
The heat released to cool water to 0°C is
Q2 = mS∆T = 1 × 1 × 100 = 100 cal.
∴ Total energy released = 540 + 100 = 640 cal.

c) How much energy is released or absorbed when 1 gm of water at 0° C freezes to ice at 0° C?
Answer:
In CGS system :
Mass of water = m = 1 gm
Latent heat of fusion of ice (L) = 80 cal/gm
The energy transferred or released when 1 gm of water at 0° C freezes to ice at 0° C.
Q = mLfreeze = 1 × 80 = 80 Cal.

(OR)

In SI system :
Mass of water = m = 1 gm = \(\frac{1}{1000} \mathrm{~kg}\)
Latent heat of fusion = L = 3.36 × 105 J/kg.
Amount of heat released or transferred when lgm of water at 0°C freezes to ice at 0°C.
Q = mLfusion = \(\frac{1}{1000} \mathrm{~kg}\) × 3.36 × 105 = 3.36 × 102 = 336J.

(OR)

In CGS system :
Mass of water = m = 1 gm
Latent heat of fusion of ice (L) = 80 cal/gm
The energy transferred or released when 1 gm of water at 0° C freezes to ice at 0°C.
Q = mLfreeze = 1 × 80 – 80 cal.
(Or)
In SI system : In SI, Q = 80 × 4.2 [1 cal = 4.2 J]
Q = 1 x 10-3 × 3.36 × 105 = 3 36 J.

d) How much energy is released or absorbed when 1 gm of steam at 100°C turns to ice at 0°C?
Answer:
In CGS system :
Mass of water = m = 1 gm
Latent heat of vapourisation = Lvapour = 540 cal/gm
Latent heat of fusion of ice = Lfusion = 80 cal
Specific heat of water = S = 1 cal/gm-0°C
Difference in temperature
∆T = 100 – 0 = 100°C.
The energy transferred when 1 gram of steam at 100°C turns to ice at 0°C
Q = mLvapour + mS∆T + mLfusion
= 1 × 540 + 1 × 1 × 100 + 1 × 80 = 540 + 100 + 80 = 720 cal.

(OR)

Mass of water = m = 1 gm = \(\frac{1}{1000} \mathrm{~kg}\)
Latent heat of vapourisation = Lvapour = 2.25 × 106 J/kg
Latent heat of fusion = Lfusion = 3.36 × 105 J/kg
Difference in temperature
∆T = 373 – 273 – 100 K.
Specific heat of water = 4180 J/kg-K
The energy transferred when 1 gram of steam at 100° C turns to ice at 0°C =
AP SSC 10th Class Physics Solutions Chapter 1 Heat 2

(OR)

In CGS system :
Conversion : Steam at 100°C → Water at 100°C → Water at 0°C → Ice at 0°C.
Mass of water = m = 1 gm
Latent heat of vapourisation = Lvapour = 540 cal/gm
Latent heat of fusion of ice = Lfusion = 80 cal
Specific heat of water = S = 1 cal/gm-0°C
Difference in temperature
∆T= 100-0 = 100°C.
The energy transferred when 1 gram of steam at 100°C turns to ice at 0°C
Q = mLvapour + mS∆T + mLfusion
= 1 × 540 + 1 × 1 × 100 + 1 × 80
= 540 + 100 + 80 = 720 cal. = 720 × 4.18 = 3009.6 J.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 7.
Explain the procedure of finding specific heat of solid experimentally. (AS1)
(OR)
Determination of specific heat of solid experimentally.
(OR)
Ravi wanted to prepare solid with high specific heat to use on cooking utensil. What fool does he need to find the specific heat of aluminium and copper? How should he conduct the experiment?
Answer:
Aim : To find the specific heat of given solid.
Apparatus : Calorimeter, thermometer, stirrer, water, steam heater, wooden box and lead shots.

Procedure:

  • Measure the mass of the calorimeter with stirrer = m1 gm
  • Fill water one third volume of calorimeter and measure the mass = m2 gm.
  • At this time initial temperature = T1.
  • Mass of the water = m2 – m1 gm.
  • Take a few lead shots and place them in steam heater and heat up to 100° C. Let this temperature be T2.
  • Transfer the lead shots into calorimeter and measure the final (or) resultant temperature T3.
  • Mass of calorimeter with contents = m3 gm and mass of lead shots = m3 – m2 gm.
  • If the specific heats of the calorimeter, lead shots and water are Sc, Sl and Sw respectively, by using method of mixtures we have
    Heat lost by the solid = Heat gained by the calorimeter + water
    AP SSC 10th Class Physics Solutions Chapter 1 Heat 3
  • Knowing the specific heats of calorimeter and water we can calculate specific heat of solid (lead shots).

Question 8.
Convert 20° C into Kelvin scale. (or) Change 20°C into absolute scale. (AS1)
Answer:
T = t°C + 273 = 20 + 273 = 293
⇒ T = 293 K.

Question 9.
Your friend is asked to differentiate between evaporation and boiling. What questions could you ask to make him to know the differences between evaporation and boiling? (AS2)
(OR)
Veena found that the water kept in a pot is cool and Siva observed when water is heated the temperature remains constant for some time until water turns into vapour. What are the processes involved in these two aspects? Ask some questions to understand these aspects.
Answer:
The questions asked by me are :

  • How do wet clothes get dried without heating?
  • Are boiling and evaporation one and same or different?
  • Is there any difference in kinetic energy if it boils?
  • Is the temperature the main cause for boiling and evaporation?
  • What are the factors which influence evaporation?
  • Is boiling temperature for water always 100° C?

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 10.
What happens to the water when wet clothes dry? (AS3)
Answer:

  1. When wet clothes dry, the water present in the clothes is evaporated.
  2. So that the process of evaporation causes the wet clothes dry.

Question 11.
Equal amounts of water are kept in a cap and in a dish. Which will evaporate faster? Why? (AS3)
(OR)
Srinu kept. equal amounts of water in a cap and in a dish in open air. What is his observation? Explain the experiment.
Answer:
Aim : To show the evaporation of equal amounts of water in cap and dish.
Apparatus : Cap, dish, water.

Procedure :

  • Take equal amounts of water in cap and dish. Keep them in open air for two hours. Now weigh the water in the cap and the dish.
  • We can observe that the weight of water in dish is less than that of water in cap.
  • This shows that the water in dish has more evaporation than the water in cap.
  • It is due to more surface area of dish.
  • As the surface area increases rate of evaporation also increases.

Question 12.
Suggest an experiment to prove that rate of evaporation of a liquid depends on its surface area and vapour already present in surrounding air. (AS3)
Answer:
Aim: The rate of evaporation of liquid depends on its surface area and vapour already present in surrounding air.
Apparatus : Two dishes of different surface areas and water.

Procedure :

  • Take two dishes of different surface area.
  • Pour equal amounts of water in the both dishes.
  • Keep aside for two to three hours.
  • Observe them after some time.
    Dish with more surface area has less quantity of water than the dish having less surface area. ,
  • This shows evaporation increases with increasing of surface area.
  • Take two dishes of equal surface area containing water.
  • This experiment should be conducted on more humid day and less humid day.
  • We will find that evaporation is less on more humid day due to more vapour in the air.
  • So evaporation decreases with vapour in the air.

Question 13.
Place a Pyrex funnel with its mouth-down in a sauce pan full of water, in such a way that the stem tube of the funnel is above the water or pointing upward into air. Rest the edge of the bottom portion of the funnel on a nail or on a coin so that water can get under it. Place the pan on a stove and heat it till it begins to boil. Where do the bubbles form first? Why? Can you explain how a natural geyser works using this experience? (AS4)
Answer:

  • When Pyrex funnel with its mouth down in a sauce pan then the bubbles formed by the heat energy come from the top of the funnel.
  • That is from stem tube.
  • This is because of pressure inside mouth of funnel increases rapidly due to increasing of heat energy.
  • Pressure inside the funnel rs more than outside the funnel and very high at stem.
  • Hence, bubbles come from stem of the funnel and escapes through stem tube with force, like a geyser.

AP SSC 10th Class Physics Solutions Chapter 1 Heat 5
Working of natural geyser by using this experience :

  • Geysers are the fountains of hot water coming under the layers of the earth.
  • It is a hole with narrow and deep from the bottom of the earth layers.
  • It contains water.
  • Water heats up due to high temperatures of the inner layers of the earth.
  • As by the pressure of water at top layers of the hole, temperature rises, water boils.
  • This hot water comes with narrow vent with high pressure, like Lava from the Volcano.

Question 14.
Collect the information about working of natural geyser and prepare a report. (AS4)
Answer:
Natural Geysers :

  • Geysers are the fountains of hot water coming under the layers of the earth.
  • It is a hole with narrow and deep from the bottom of the earth layers.
    AP SSC 10th Class Physics Solutions Chapter 1 Heat 6
  • It contains water.
  • Water heats up due to high temperatures of the inner layers of the earth.
  • As by the pressure of water at top layers of the hole, temperature rises, water boils.
  • This hot water comes with narrow vent with high pressure, like Lava from the Volcano.
  • This looks like a water fountain at the surface of the earth.
    AP SSC 10th Class Physics Solutions Chapter 1 Heat 7

Question 15.
Assume that heat is being supplied continuously to 2 kg of ice at – 5°C. You know that ice melts at 0°C and boils at 100°C. Continue the heating till it starts boiling. Note the temperature for every minute. Draw a graph between temperature and time using the values you get. What do you understand from the graph ? Write the conclusions. (AS5)
Answer:
Graph between time and temperature from ice melting at 5° C to boils at 100° C.
AP SSC 10th Class Physics Solutions Chapter 1 Heat 8

Understanding from the graph :

  • \(\overline{\mathrm{AB}}\) = Ice warms up from – 5°C to 0°C
  • \(\overline{\mathrm{BC}}\) = Ice melts at 0°C for a certain time period. So \(\overline{\mathrm{BC}}\) indicates no rising in temperature.
  • \(\overline{\mathrm{CD}}\) = Water warms up from 0°C to 100° C, \(\overline{\mathrm{CD}}\) indicates rising in temperature.
  • \(\overline{\mathrm{DE}}\) = Water boils at 100° C for a certain time period. So \(\overline{\mathrm{DE}}\) indicates no rising in temperature.

Conclusion :

  • The temperature remains same at 0° C until all the ice converted into water. So, 0° C is the melting point of water.
  • The temperature remains constant at 100° C until all the water converted into water vapour. So, 100° C is the boiling point of the water.

Question 16.
How do you appreciate the role of the higher specific heat of water in stabilising atmospheric temperature during winter and summer seasons? (AS6)
Answer:

  • Due to higher specific heat of water oceans absorb the solar energy for maintaining a relatively constant temperature.
  • Oceans absorb large amounts of heat at the equator.
  • The oceans moderate the surrounding temperature near the equator.
  • Ocean water transports the heat away from the equator to areas closer to the north and south pole.
  • This transported heat helps moderate the climate in parts of the Earth that are far from the equator.
  • So higher specific heat of water is stabilising atmospheric temperature.
  • So we have to extremely appreciate the role of higher specific heat of water to stabilise the atmospheric temperature.

Question 17.
Suppose that 1 / of water is heated for a certain time to rise and its temperature by 2°C. If 2 l of water is heated for the same time, by how much will its temperature. (AS7)
Answer:
Mass of 1 litre of water (m1) = 1 kg ; ∆T1 = 2°C
Mass of 2 litres of water (m2) = 2 kg ; ∆ T2 = ?
Time duration is same. So same heat is absorbed by water in both the cases
⇒ Q1 = Q2
m1S(∆T1) = m2S (∆T2)
AP SSC 10th Class Physics Solutions Chapter 1 Heat 9
So the rise in temperature for 2 kg of water = 1°C.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 18.
What role does specific heat play in keeping a watermelon cool for a long time after removing it from a fridge on a hot day? (AS7)
Answer:

  • Generally, watermelon contains large percentage of water.
  • Water has high specific heat value than other substances.
  • High specific heat substances oppose the increase of temperature. Hence they continuous of the coolingness.
  • So watermelon retains coolness after removing from fridge on a hot day due to the high specific cheat of water.

Question 19.
If you are chilly outside the shower stall, why do you feel warm after the bath if you stay in bathroom? (AS7)
Answer:

  • In the bathroom, the number of vapour molecules per unit volume is greater than the number of vapour molecules per unit volume outside the room.
  • When we try to dry ourselves with a towel, the vapour molecules surrounding you condense on your skin.
  • Condensation is a warming process.
  • Because of the condensation, you feel warm outside the shower stall when it is chilly.

Question 20.
Three objects A at 30°C, B at 303K and C at 420 K are in thermal contact. Then answer the follwing questions.
(i) Which are in “Thermal equibrium” among A, B and C?
(ii) From which object to another heat transferred? (2 Marks)
Answer:
i) 303K – 273K + 30K = 0°C + 30°C = 30°C.
∴ A and B objects are in ‘Thermal equibrium”.
ii) From object ‘C’ to objects ‘A’ and ‘B’ heat transferred.

Fill in the Blanks

1. The SI unit of specific heat is …………………. .
2. …………………. flows from a body at higher temperature to a body at lower temperature.
3. …………………. is a cooling process.
4. An object A at 10° C and another object B at 10 K are kept in contact, then heat will flow from …………………. to …………………. .
5. The latent heat of fusion of ice is …………………. .
6. Temperature of a body is directly proportional to …………………. .
7. According to the principle of method of mixtures, the net heat lost by the hot bodies is equal to …………………. by the cold bodies.
8. The sultryness in summer days is due to
9. …………………. is used as a coolant.
10. Ice floats on water because …………………. .
Answer:

  1. J/kg – K
  2. Heat
  3. Evaporation
  4. A, B
  5. 80 cal/gm
  6. Average kinetic energy of the molecules of the body.
  7. net heat gained
  8. high humidity
  9. Water
  10. the density of ice is less than that of water

Multiple Choice Questions

1. Which of the following is a warming process?
A) evaporation
B) condensation
C) boiling
D) all the above
Answer:
B) condensation

AP SSC 10th Class Physics Solutions Chapter 1 Heat

2. Melting is a process in which solid phase changes to ………………. .
A) liquid phase
B) liquid phase at constant temperature
C) gaseous phase
D) any phase
Answer:
B) liquid phase at constant temperature

3. Three bodies A, B and C are in thermal equilibrium. The temperature of B is 45° C. Then the temperature of C is ……………… .
A) 45° C
B) 50° C
C) 40° C
D) any temperature
Answer:
A) 45° C

4. The temperature of a steel rod is 330 K. Its temperature in ° C is ……………… .
A) 55° C
B) 57° C
C) 59° C
D) 53° C
Answer:
B) 57° C

5. Specific heat S =
AP SSC 10th Class Physics Solutions Chapter 1 Heat 4
Answer: C

6. Boiling point of water at normal atmospheric pressure is ……………… .
A) 0° C
B) 100° C
C) 110° C
D) -5° C
Answer:
B) 100° C

AP SSC 10th Class Physics Solutions Chapter 1 Heat

7. When ice melts, its temperature ……………… .
A) remains constant
B) increases
C) decreases
D) cannot say
Answer:
A) remains constant

10th Class Physics 1st Lesson Heat InText Questions and Answers

10th Class Physics Textbook Page No. 1

Question 1.
Take a piece of wood and a piece of metal and keep them in a fridge or ice box. After 15 minutes, take them out and ask your friend to touch them. Which is colder? Why?
Answer:
1) The metal piece is colder than the wooden piece.
2) Because more heat energy flows out of our body so metal piece gives coldness to our body, than wooden piece.

Question 2.
What could be the reason for difference in coldness of metal and wood?
Answer:

  • Due to more heat energy loss by our body when touches the metal piece compared to the wooden piece.
  • In other way we say degree of coldness of the metal piece is greater than that of. the wooden piece.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 3.
Does it have any relation to the transfer of heat energy from our body to the object?
Answer:

  • Yes, the principle of calorimetry, means heat loss by hot body is equal to heat gained by cold body.
  • This means that when heat energy flows out of our body we feel the coldness and when heat energy enters our body we feel hotness.

10th Class Physics Textbook Page No. 2

Question 4.
Why does transfer of heat energy take place between objects?
Answer:

  • Due to the temperature difference between the two bodies which are in thermal contact.
  • Now heat energy transfers from hot body to cold body until they attain same temperature.

Question 5.
Does transfer of heat take place in all situations?
Answer:
No, when the bodies are in thermal equilibrium there is no transfer of heat energy.

Question 6.
What are the conditions for transfer of heat energy?
Answer:

  • Two bodies should have difference in temperature.
  • They (two bodies) are in thermal contact with each other.
  • When the bodies have equal temperature there is no transfer of heat energy.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 7.
What is temperature?
(OR)
Define temperature.
Answer:
Temperature : The measure of hotness or coldness of a body is called temperature.

Question 8.
How can you differentiate temperature from heat?
Answer:

  • Heat is a thermal energy that flows from hot body to cold body. Temperature is measure of the hotness or coldness of a body.
  • Temperature decides direction of heat (energy) flow, whereas heat is energy itself that flows.

10th Class Physics Textbook Page No. 2 & 3

Question 9.
Place a laboratory thermometer in a glass tumbler containing hot water. Observe the change in mercury level. Wffet change did you notice in mercury level? Did mercury level increase or decrease?
Answer:
The mercury level rises up that means temperature of the mercury level increases.

10th Class Physics Textbook Page No. 3

Question 10.
Place a laboratory thermometer in a glass tumbler containing cold water. Observe the change in mercury level. Did mercury level decrease or increase?
Answer:
The mercury level falls down that shows temperature of the mercury level decreases.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 11.
If two different systems A and B in thermal contact, are in thermal equilibrium individually with another system C (thermal contact with A and B), will the systems A and B be in thermal equilibrium with each other?
Answer:
Yes, A and B will be in thermal equilibrium with each other that means A and B will have equal temperatures.

Question 12.
How would you convert degree Celsius to Kelvin?
Answer:
Temperature in Kelvin = 273 + Temperature in degree Celsius. [K = t°C + 273]

10th Class Physics Textbook Page No. 4

Question 13.
Take two bowls one with hot water and second with cold water. Gently sprinkle food colour on the surface of the water in both bowls. How do food grains move? Why do they move randomly?
Answer:
We will notice that the grains of food colour move randomly (jiggle). This happens because of the molecules of water on both bowls are in random motion.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 14.
Why do the grains in hot water move more rapidly than the grains in cold water?
Answer:

  • Temperature kinetic energy. So molecules in hot water have more KE than molecules in cold water.
  • As water molecules in hot water move rapidly, grains in hot water move more rapidly than the grains in cold water.

10th Class Physics Textbook Page No. 4 & 5

Question 15.
a) Take a cylindrical jar and pour hot water and then coconut oil in the vessel (do not mix them). Keep thermometers in hot water and coconut oil as shown in figure. The reading of thermometer in hot water decreases, at the same time reading of the thermometer, kept in oil increases. Why does this happen?
Answer:
AP SSC 10th Class Physics Solutions Chapter 1 Heat 10

  • Heat transfers from hot water to oil.
  • So, water loses heat and shows downfall in temperature.
  • Oil takes the heat and shows increasing in the temperature.

b) Can you say that water loses energy’?
Answer:

  • Yes. Due to the temperature difference between the water and oil, water loses energy and oil gains energy.
  • Thus some heat energy flows from water to oil.
  • This means, the kinetic energy of the molecules of water decreases while the kinetic energy of molecules of oil increases.

c) Can you differentiate between heat and temperature based on the heat transmit activity?
Answer:
Heat is the energy that flows from a hotter body to a colder body. Temperature denotes which body is hotter and which is colder. So, temperature determines direction of heat (energy) flow, whereas heat is the energy that flows.

10th Class Physics Textbook Page No. 5 & 6

Question 16.
Place two test tubes containing 50 gm of water, 50 gm of oil in boiling water for same time.
a) In which material does the temperature rise quickly? Are the amounts of heat given to the water and oil same? How can you assume this?
Answer:

  • Rise in temperature of oil is faster than the water.
  • Yes, same amount of heat energy given to both the oil and water through boiling water.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

b) Why does this happen in specific heat?
Answer:
This happens because rise in temperature depends on the nature of substance.

10th Class Physics Textbook Page No. 7

Question 17.
How much heat energy is required to rise the temperature of unit mass of substance (material) by 1°C?
Answer:
Energy equal to its specific heat.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 18.
Why is the specific heat different for different substances?
(OR)
Explain why specific heat values are different for different materials.
Answer:

  • We know that the temperature of the body is directly proportional to the average kinetic energy of particle of the body.
  • The molecules of the system have different forms of energies such as linear, rotational kinetic energy, vibrational energy and potential energy.
  • When we supply heat energy, it will be shared in different forms and increase the energy in the system.
  • This sharing will vary from material to material.
  • If the maximum share of heat energy is spent to rise linear kinetic energy, then the system gets increasing in temperature.
  • Due to differences in sharing different materials have different specific heats.

10th Class Physics Textbook Page No. 8

Question 19.
Take 200 ml of water in two beakers and heat them to same temperature and pour the water of two beakers into a larger beaker.
What do you observe? What could be the reason for the fact you observed?
Answer:

  • The temperature of mixture remains the same.
  • The reason is that the masses rise in temperature and the materials are same.

Question 20.
Heat the water in one beaker to 90°C and the other to 60°C. Mix the water from these beakers in large beaker. What will be the temperature of the mixture? What did you notice? Can you give reason for the change in temperature?
Answer:

  • The temperature of mixture is 75°C.
  • The reason is for a given material the temperature of mixture,
    AP SSC 10th Class Physics Solutions Chapter 1 Heat 12
  • Hot water gives heat to the cold water until thermal equilibrium takes place.
  • So, the thermal equilibrium attains at 75°C.

Question 21.
ake 100 ml of water at 90°C and 200 ml of water at 60°C and mix the two. What is the temperature of the mixture? What difference do you notice in change of temperature?
Answer:

  • The temperature of mixture is 70°C.
  • The reason is here m1 = 100 gm ; m2 = 200 gm
    AP SSC 10th Class Physics Solutions Chapter 1 Heat 13
  • Final temperature of the mixture is less than the above case.
  • If the quantity increases, the quantity of heat to transfer is also rises to attain thermal equilibrium.
    Here hotter body quantity is less and colder body quantity is high. So, the temperature at thermal equilibrium decreases and stands at 70° C.

10th Class Physics Textbook Page No. 10

Question 22.
When floor of room is washed with water, the water on the floor disappears within minutes. Why does water on the floor disappear after some time?
Answer:
Due to evaporation water disappears from the floor.

Question 23.
Pour a few drops of spirit on your palm. Why does your skin become colder? (1 Mark)
Answer:
Spirit absorbs heat energy from our palm and evaporates. So our palm becomes colder.

10th Class Physics Textbook Page No. 10 & 11

Question 24.
Take a few drops of spirit in two petri dishes separately. Keep one of the dishes under a ceiling fan and switch on the fan. Keep another dish with its lid closed. What do you notice? What could be the reason for this change?
Answer:
1) The spirit in the dish which is kept under the ceiling fan disappears.
2) Whereas we will find some spirit left in the dish that is kept in the lidded dish.
3) The molecules which are escaping from the surface is high and they can’t reach back to liquid due to wind blow. So, evaporation is high under fan.
4) At the same time evaporation is less in the dish which is closed by lid.

10th Class Physics Textbook Page No. 12

Question 25.
Does the reverse process of evaporation take place? When and how does it take place?
Answer:
1) Yes, the reverse process of evaporation takes place.
2) When the vapour molecules lose their kinetic energy which leads to lower the temperature, they convert into droplets.
3) This process is called condensation.

10th Class Physics Textbook Page No. 13

Question 26.
In early morning, during winter, you might have noticed that water droplets form on window panes, flowers, grass, etc. How are these water droplets formed?
(OR)
Why do water drops (dew) form on flowers and grass during morning hours of winter season?
Answer:

  • During winter season, in the night times, atmospheric temperature goes down.
  • The surfaces of window panes, flowers, grass, etc. become colder.
  • The water vapour molecules touch the surfaces, gets cooled and lost its energy.
  • Then water vapour condenses on the surface and water drops formed.
  • The water droplets condensed on such surfaces are known as dew.

10th Class Physics Textbook Page No. 14

Question 27.
Are the process of evaporation and boiling the same? Explain.
Answer:

  • No, they are different.
  • Evaporation takes place at any temperature.
  • But boiling occurs at particular temperature called the boiling point.

10th Class Physics Textbook Page No. 16

Question 28.
You might have observed coconut oil and ghee getting converted from liquid state to solid state during winter season. What could be the reason for this change? What happens to water kept in a refrigerator? How does it get converted from liquid phase to solid phase?
Answer:
1) If temperature of a substance decreases kinetic energy also decreases.
2) Kinetic energy decreases from water to ice. That means solid state to liquid state.
3) In winter season coconut oil in the form of liquid get down its temperature, hence its kinetic energy also decreases. So, it-freezes.
4) Water, which is kept in refrigerator loses the kinetic energy along with decreasing temperature and freezes.
5) In this way water converted liquid phase to solid phase.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

Question 29.
Are the volumes of water and ice formed with same amount of water equal? Why?
Answer:
1) No, the volume of ice is greater than volume of water.
2) Water expands on freezing.
3) That means density of ice is less than density of water.

10th Class Physics 1st Lesson Heat Activities

Activity – 1

1. Explain the term temperature with example.
(OR)
What is the name given to degree of hotness or coldness? Explain the quantity with an example.
Answer:
Procedure: Take a piece of wood and a piece of metal and keep them in fridge or ice box.
Observation : When we touch both of them we feel that metal piece is colder than the wooden piece.

Explanation :

  • This is due to more energy flow out of our body when we touch the metal piece as compared with wooden piece.
  • The degree of coldness of metal is greater than that of the wooden piece.
  • The degree of hotness or coldness is called temperature.
  • From this example, we say metal piece is at a lower temperature compared to wooden piece.

Activity – 2

2. What is the measure of thermal equilibrium? How do you prove?
(OR)
How do you prove temperature is the measure of thermal equilibrium?
(OR)
Explain thermal equilibrium with an activity.
Answer:
Procedure :
Take two glass tumblers and fill one of them with hot water and another with cold water.
Explanation & Observation :
1) When we place a thermometer inside the hot water the mercury level of thermometer rises from initial position due to heat transferred from hotter body (hot water) to colder body (mercury in thermometer).
2) When we place the thermometer inside the cold water the mercury level comes down from its initial position due to transfer of heat from mercury (hotter body) to water (colder body).

Conclusion :

  • Heat is a form of energy that flows from a body at higher temperature to a body at lower temperature until the temperature remains same for two bodies that is called thermal equilibrium.
  • In the above case, the steadiness of mercury column shows that thermal equilibrium is achieved. That reading of mercury column gives temperature.
  • Thus temperature is a measure of thermal equilibrium.

Activity – 3

3. Establish the relationship between temperature and average kinetic energy.
(OR)
Suggest an activity to prove that the average kinetic energy of the molecules is directly proportional to the absolute temperature of the substances.
(OR)
How do you prove that temperature of a body is an indicator of average kinetic energy?
Answer:
Procedure :

  • Take two bowls one with hot water and second with cold water.
  • Gently sprinkle food colour on the surface of the water in both bowls.

Observation :
We will observe the jiggling of grains of food colour in hot water is more when compared to jiggling in cold water.

Explanation :

  • We know kinetic energy depends on speed motion of particles.
  • So the kinetic energy of hotter body is greater than that of colder body.
  • Thus the temperature of a body is an indicator of average kinetic energy of molecules of that body.

Conclusion :
Therefore average kinetic energy of molecules is directly proportional to absolute temperature.

Activity – 4

4. Write an activity which tells how heat transmits.
(OR)
In which direction does heat tend to flow? Prove it with an activity.
Answer:
AP SSC 10th Class Physics Solutions Chapter 1 Heat 10
Procedure :

  • Take water in a container and heat it to 60° C.
  • Take a cylindrical transparent glass jar and fill half of it with the hot water.
  • Pour coconut oil over the surface of water.
  • Put a lid with two holes on the top of the glass jar.
  • Insert two thermometers through the lid in such a way that one inside coconut oil and other in water.

Observation & Explanation :

  • Now we can observe that the reading of thermometer kept in water decreases while the reading of thermometer kept in oil increases.
  • So temperature of water decreases whereas temperature of oil increases.

Conclusion :

  • Heat transmits from hotter body to colder body.
  • So temperature determines direction of heat flow.

Activity – 5 Specific Heat

5. Write an activity which gives the relation between rise in temperature and nature of material.
(OR)
“The rate of rise in temperature depends on the nature of substance.” Prove it with an activity.
(OR)
Draw a diagram and label the parts to prove that the rate of increase in temperature depends on the nature of substance.
(OR)
We can observe severe burns with hot oil when compared with hot water.
Which factor will decide this aspect? Explain this process with an example.
Answer:
Procedure :

  • Take a large jar with water and heat it up to 80°C.
  • Take two identical boiling test tubes with single-holed corks.
  • Fill them, one of the boiling tubes with 50 gm of water and other with 50 gm of oil.
  • Insert two thermometers in each of tubes and clamp them to retort stand and place them in a jar of hot water.

Observation :

  • Observe the readings of thermometers every three minutes.
  • We can observe that the rise in temperature of oil is higher than that of water.

AP SSC 10th Class Physics Solutions Chapter 1 Heat 11

Explanation :

  • Since both the boiling tubes kept in hot water for the same interval of time, the heat supplied to oil and water is same but rise in temperature of oil is more.
  • So we conclude that rise in temperature depends on the nature of substance (specific heat).

Activity – 6

6. Derive Q = mSAT.
(OR)
Establish relationship between heat energy, mass of the substance and rise in temperature.
(OR)
Derive an expression for heat energy.
(OR)
Derive an expression for factors affecting amount of heat energy absorbed.
Answer:
Procedure :

  • Take two beakers of equal volume and take 250 grams of water in one beaker and 1 kg of water in another beaker.
  • Note their initial temperatures.
  • Now heat the two beakers up to 60° C.
  • Note down the heating times.

Observation:

  • We observe that-the water in large beaker takes more time.
  • That means we need to supply more heat enepgy to water in larger beaker (greater quantity of water).

Conclusion :
From this we conclude that for some change in temperature the amount of heat (Q) absorbed by a substance is directly proportional to its mass (m).
Q ∝ m (when ∆T is constant) ………….. (1)

Procedure :
Now take 1 litre of water in a beaker and heat it and note the temperature changes (∆T) for every two minutes and observe the rise internals.

Conclusion:
We will notice that for the same mass (m) of water the change in temperature is proportional to amount of heat (Q) absorbed by it.
Q ∝ ∆T (when m is constant) ………….. (2)
From (1) and (2) Q m∆T (or) Q = mS∆T,
where ‘S’ is called specific heat of substance.

Activity – 7

7. a) How are you able to find the final temperature of the mixture of sample?
(OR)
What is the “Principle of method of mixtures”? Verify it with an activity.
Answer:
Situation – 1 :

  • Take two beakers of the same size and pour 200 ml of water in each of them.
  • Now heat the water in both beakers to same temperature.
  • Now pour water from these beakers into a larger beaker and measure the temperature of the mixture.

Observation :
We can observe that there is no change in temperature.

Situation – 2 :

  • Now heat the water in first beaker to 90° C and the other to 60° C.
  • Mix the water from these beakers in a large beaker.

Observation :
We can find that the temperature of mixture is 75° C.

Situation – 3 :
Now take 100 ml of water at 90° C and 200 ml of water at 60° C and mix the two. Observation :
We can find that the temperature of mixture is 75° C.

AP SSC 10th Class Physics Solutions Chapter 1 Heat

7. b) Derive, a formula for final temperature of mixture of samples.
(OR)
Maveen added hotter water of mass m1 kept at temperature T1 to cold water of mass m2 kept at temperature T2. Find the expression to find temperature of mixture of samples.
Answer:
Procedure:
1) Let the initial temperatures of the hotter and colder samples of masses m1 and m2 be T1 and T2.
2) Let T be the final temperature of mixture.

Observation :
The temperature of the mixture is lower than hotter sample and higher than colder sample. Explanation :
So hot sample has lost heat, and the cold sample has gained heat.
The heat lost by the hot sample Q1 = m1S (T1 – T)
The heat gained by the cold sample Q2 = m2S (T – T2)
We know that heat lost = heat gained
Q1 = Q2
m1 S(T1 – T) = m2 S(T – T2)
\(\mathrm{T}=\frac{\mathrm{m}_{1} \mathrm{~T}_{1}+\mathrm{m}_{2} \mathrm{~T}_{2}}{\mathrm{~m}_{1}+\mathrm{m}_{2}}\)

Activity -8

8. Explain the process of evaporation phenomenon with an example.
(OR)
Srinu observed that spirit taken in a petri dish disappears after some time. Explain the process involved in it with an example.
Answer:
Procedure :

  • Take a few drops of spirit in two petri dishes separately.
  • Keep one of the dishes under a ceiling fan and keep another dish with its lid closed.
  • Observe the quantity of spirit in both dishes after 5 minutes.

Observation :
We will notice that spirit in the dish kept under the ceiling fan disappears whereas we will find some spirit left in the dish that is kept in the lidded dish.

Explanation :

  • The reason is that the molecules of spirit in dish continuously move with random speeds and collide with other molecules.
  • During the collision they transfer energy to other molecules.
  • Due to this collision the molecules at the surface acquire energy and fly off from the surface.
  • Some molecules come back to liquid.
  • If the number of escaping molecules is greater than returned number, then the number of molecules in the liquid decreases.

Conclusion :
When a liquid is exposed to air, the molecules at the surface keep on escaping from the surface till the entire liquid disappears into air. This process is called evaporation.

Activity – 9

9. Explain the process of condensation with example.
(OR)
Explain the process of condensation with an activity.
(OR)
Karan told his friend that he observed that there are some water droplets outside a cold soft drink bottle. Explain the phenomenon involved in the formation of these droplets.
Answer:
Procedure :
Place a glass tumbler on the table. Pour cold water up to half of its height.

Observation :
There are droplets formed outside of the glass.

Explanation :

  • The reason is that the surrounding air contains water molecules in the form of water vapour. When the water molecules strike the surface of the glass tumbler which is cool, they lose their kinetic energy.
  • This energy lowers the temperature of vapour and it turns into droplets.
  • The energy lost by water molecules in air is gained by the molecules of the glass tumbler.
  • Hence the average kinetic energy of glass molecules increases. In turn the energy is transferred to water molecules in die glass.

Conclusion :

  • So the average kinetic energy and temperature of water in glass increases. This is called condensation.
  • Condensation is the phase change from gas to liquid.

Activity – 10

10. Explain the process of boiling with an example.
(OR)
Why do we observe bubbles on the surface of water which has been heated ? What is the phenomenon involved in it? Explain.
Answer:
Procedure :
Take a beaker of water, keep it on the burner and note the readings of thermometer for every two minutes.

Observation :

  • We will notice that the temperature of the water rises continuously till it reaches 100° C.
  • Once it reaches 100° C the temperature remains same and a lot of bubbling on the surface takes place. This is called boiling of water.

Explanation :

  • It happens due to when water is heated the solubility of gases it contains reduces.
  • As a result, bubbles of gas are formed in the liquid.
  • Evaporation of water molecules from the surrounding liquid occurs into these bubbles and they become filled with saturated vapour.
  • At a certain temperature, the pressure of the saturated vapour inside the bubbles becomes equal to the pressure exerted on the bubbles from the outside.

Conclusion :

  • As a result, these bubbles rise rapidly to the surface and collapse at the surface releasing vapour present in bubbles into air at the surface. This process is called “boiling”.
  • This temperature is called ‘boiling temperature”.

Activity – 11

11. Explain the process of melting and latent heat of fusion.
(OR)
When ice is heated to 0°C it starts to turn into water. But temperature remains ‘ constant for some time. What is the process involved in this? Explain.
Answer:
Procedure :

  • Take small ice cubes in a beaker. Insert the thermometer in the beaker.
  • Now start heating the beaker and note down readings of thermometer every one minute till the ice completely melts and gets converted into water.
  • Before heating the temperature of ice is 0°C or less than 0°C.

Observation :

  • We will observe that the temperature of ice at the beginning is equal to or below 0°C.
  • If the temperature of ice is below 0°C, it goes on changing till it reaches 0°C.
  • When ice starts melting, we will observe no change in temperature though you are supplying heat continuously.

Explanation:

  • Given heat energy uses to break the bonds (H2O) in ice and melts.
  • So, temperature is constant while melting.

Conclusion:

  • This process is called melting. In this process, heat converts solid phase to liquid phase.
  • The temperature of the substance does not change until all the ice melts and converts into water.
  • The heat given to melting is called latent heat of fusion.
  • The heat required to convert 1 gm of solid completely into liquid at constant temperature is called “latent heat of fusion”.

Activity – 12

12. Why does a glass bottle tilled with water break when it is placed in deep freezer for some time?
(OR)
Prove that density of ice is less than that of water.
(OR)
How do you prove that volume of ice is more than that of water?
Answer:
Procedure :

  • Take a small glass bottle with a tight lid and fill it with water, without any gap and fix the lid tightly.
  • Put the bottle into the deep freezer of a refrigerator for a few hours.

Observation :
When we take it out from the deep freezer, we can observe that the glass bottle breaks.

Explanation :

  • These cracks on the bottle due to expansion of the substance in the bottle.
  • This means water expands on freezing.

Conclusion :

  • Water expands on freezing.
  • Ice has less density than water.