NCERT Solutions for Class 7 Science Chapter 10 Respiration In Organisms are provided here with simple step-by-step explanations. These solutions for Respiration In Organisms are extremely popular among Class 7 students for Science Respiration In Organisms Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the NCERT Book of Class 7 Science Chapter 10 are provided here for you for free. You will also love the ad-free experience on Meritnation’s NCERT Solutions. All NCERT Solutions for class Class 7 Science are prepared by experts and are 100% accurate.
Page No 52:
Question 1:
Sometimes when we do heavy exercise, anaerobic respiration takes place in our muscle cells. What is produced during this process?
(a) alcohol and lactic acid
(b) alcohol and CO2
(c) lactic acid and CO2
(d) lactic acid only
Answer:
Lactic acid is produced as a result of anaerobic respiration that takes place in our muscle cells during heavy exercise. During anaerobic respiration, partial breakdown of glucose produces lactic acid and its accumulation in muscles causes muscular cramps.
Hence, the correct answer is option (d).
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Question 2:
Yeast is used in wine and beer industries because it respires
(a) aerobically producing oxygen.
(b) aerobically producing alcohol.
(c) anaerobically producing alcohol.
(d) anaerobically producing CO2.
Answer:
Yeast can survive in the absence of air and are called anaerobes. Yeast is used in the wine and beer industries because it respires through anaerobic respiration. Glucose breaks down into alcohol and carbon dioxide in the absence of oxygen.
Hence, the correct answer is option (c).
Page No 52:
Question 3:
During the process of exhalation, the ribs move
(a) down and inwards.
(b) up and inwards.
(c) down and outwards.
(d) up and outward.
Answer:
During the process of exhalation, the ribs move down and inwards whereas the diaphragm moves up. During this process, the size of the chest cavity reduces and the air is pushed out of the lungs.
Hence, the correct answer is option (a).
Page No 52:
Question 4:
Breathing is a process that
(i) provides O2 to the body.
(ii) breaks down food to release energy.
(iii) helps the body to get rid of CO2.
(iv) produces water in the cells.
Which of the following gives the correct combination of functions of breathing?
(a) (i) and (ii) (b) (ii) and (iii)
(c) (i) and (iii) (d) (ii) and (iv)
Answer:
Breathing is the process of taking in air rich in oxygen and giving out air rich in carbon dioxide with the help of respiratory organs.
Hence, the correct answer is option (c).
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Question 5:
Fish breathe with the help of gills which are richly supplied with blood vessels. The gills help the fish to
(a) take in oxygen from air.
(b) take in oxygen dissolved in water.
(c) absorb nutrients present in water.
(d) release waste substances in water.
Answer:
Gills are projections of the skin. In fish, they help them to use oxygen dissolved in water. Gills are well supplied with blood vessels for the exchange of gases.
Hence, the correct answer is option (b).
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Question 6:
Earthworms and frogs breathe through their skin because of which the skin of both the organisms is
(a) moist and rough.
(b) dry and rough.
(c) dry and slimy.
(d) moist and slimy.
Answer:
The skin of an earthworm and frog is moist and slimy due to which the gases can easily diffuse through them. So, they use their skin to breathe.
Hence, the correct answer is option (d).
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Question 7:
Mark the following statements as True or False. Correct the false statements.
(a) Oxygen breaks down glucose outside the cells of organisms.
(b) Frogs can breathe through their skin as well as lungs.
(c) Insects have spiracles on the lower surface of the body.
(d) Exhaled air has more percentage of CO2 than inhaled air.
Answer:
(a) False, Oxygen breaks down glucose inside the cells of organisms.
(b) True
(c) False, Insects have spiracles on the sides of its body.
(d) True
Page No 53:
Question 8:
Fill in the blanks with suitable words.
(a) The roots of a plant take up oxygen from the ______ trapped between the ________ particles.
(b) Diaphragm forms the ___________ of the chest cavity.
(c) Exchange of gases in the leaves take place with the help of __________.
(d) Cockroaches breathe with the help of air tubes called ___________.
Answer:
(a) The roots of a plant take up oxygen from the air trapped between the soil particles.
(b) Diaphragm forms the floor of the chest cavity.
(c) Exchange of gases in the leaves take place with the help of stomata.
(d) Cockroaches breathe with the help of air tubes called tracheae.
Page No 53:
Question 9:
Pick the odd-one-out from each of the groups given below on the basis of respiratory organs. Give reason for your answer.
(a) cockroach, grasshopper, snail, ant
(b) lizard, cow, earthworm, snake
(c) crocodile, whale, dolphin, fish
(d) snake, tadpole, crow, goat
Answer:
(a) Snails; Cockroach, grasshopper and ants have a network of air tubes called tracheae for gaseous exchange while snails do not have such a system.
(b) Earthworm; Only earthworm can breathe through its skin while the other three can breathe through the lungs.
(c) Fish; Fishes breathe through gills while the other three have lungs for respiration.
(d) Tadpole; Tadpoles breathe through gills while others have lungs.
Page No 54:
Question 10:
Which gas present in air is essential for aerobic respiration? What is the role of oxygen during respiration?
Answer:
Oxygen is essential for aerobic respiration. Oxygen in the air helps in the breakdown of food. The process of breakdown of food in the cell with the release of energy is called cellular respiration.
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Question 11:
On an average, an adult human being at rest breathes 15–18 times per minute. The breathing rate, however, may differ under different conditions. Arrange the following activities given in the box in order of increasing breathing rates and give reason for your answer.
sleeping, cycling, brisk walk, watching T.V.
Answer:
Activities in order of increasing breathing rate-
After heavy exercises such as running or cycling, the body requires extra energy. The breathing rate tremendously increases to provide more oxygen to the body. Thus, the oxygen taken in will aid in cellular respiration. When the body is at rest like sleeping or sitting, the amount of oxygen required is minimal. Hence, the breathing rate is also minimum.
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Question 12:
On a very cold morning, Boojho and Paheli were talking with each other as they walked down to their school. They observed that the air coming out of their mouth looked like smoke. They were amused and wondered how it happened. Help them find the answer.
Answer:
In winters, the atmospheric air is cold while the air we breathe out is warm, so the warm air when comes in contact with the cold air condenses to form mist which looks like smoke coming out of our mouth.
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Question 13:
Whenever we feel drowsy or sleepy, we start yawning. Does yawning help us in anyway?
Answer:
When we feel drowsy or sleepy our breathing rate slows down and the lungs do not get enough oxygen. Yawning helps us to get more oxygen to the lungs and helps us being awake.
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Question 14:
Insects and leaves of a plant have pores through which they exchange gases with the atmosphere. Can you write two points of differences between these pores with respect to their position, number and extension into the body.
Answer:
| Pores on leaves | Pores on insects |
| The pores on leaves are known as stomata. | The pores on insects are known as spiracles. |
| Stomata are present on both the upper and lower surfaces of leaves. | Spiracles are present on the sides of the body of insects. |
| Stomata are more in number. | Spiracles are less in number when compared to stomata. |
Page No 54:
Question 15:
Paheli participated in a 400 m race competition held at her school and won the race. When she came home she had mixed feelings of joy and pain as she had cramps in her leg muscles. After a massage she was relieved of the pain. Answer the following questions related to the situation.
(a) What can be the possible reasons for the pain in her legs?
(b) Why did she feel comfortable after a massage?
Answer:
(a) Due to excessive physical activity, the muscle cells undergo anaerobic respiration and result in lactic acid formation. Accumulation of lactic acid caused pain and cramps in Paheli's legs.
(b) Hot water bath or massage improves circulation of blood. As a result, the supply of oxygen to the muscle cells increases. The increase in the supply of oxygen results in the complete breakdown of lactic acid into carbon dioxide and water.
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Question 16:
Observe in the given figure carefully and answer the following questions.
(a) In which jar, will the amount of CO2 be the highest and why?
(b) In which jar, will the amount of CO2 be the lowest and why?
 |
|
|
| (A) | (B) | (C) |
Answer:
(a) The amount of CO2 will be highest in jar C due to the presence of only mice which will breathe out CO2
(b) The amount of CO2 will be lowest in jar A due to the presence of only plant which will release more oxygen and consume all the CO2
Page No 55:
Question 17:
Observe in the given figure carefully and answer the following questions.
(a) Which process is being tested in the activity?
(b) What is the result of the activity? Give reasons.
|
||
| (A) | (B) | |
Answer:
(a) The process of exhalation during respiration is being tested in the activity.
(b) In test tube A, the water remains unchanged while in test tube B, the lime water mixes with carbon dioxide in the exhaled air, and turns it milky in appearance.
Page No 56:
Question 18:
A food stall owner was preparing dough for making bhaturas. He added a pinch of yeast and sugar to the dough and left it in a warm place. After few hours, the dough had risen. There was a sour smell too.
(a) Why did the dough rise?
(b) Why did the dough smell sour?
(c) Why was sugar added to the dough?
(d) What would have happened if the dough was kept in the refrigerator, soon after it was prepared?
Answer:
(a) Due to the CO2 production by Yeast made the dough rise.
(b) The sour smell arises due to the formation of alcohol during anaerobic respiration by Yeast.
(c) Sugar acts as food for Yeast for anaerobic respiration.
(d) In the refrigerator the temperature decreases that will not allow the yeast to respire and the dough will not rise.
Page No 56:
Question 19:
Observe the figures given as in the given figure (A) and (B) and answer the following.
(a) Which of the figures A or B indicates the process of inhalation and which the process of exhalation?
(b) In the figure label the arrows and indicate the direction of
(ii) movement of diaphragm
(iii) movement of ribs
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|
|||||
| (A) | (B) | |||||
Answer:
(a) Figure A indicates inhalation and figure B indicates exhalation.
(b) IMAGE
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Question 20:
Match the names of organisms in Column I with their organs of breathing given in Column II.
| Column I | Column II |
| (a) Butterfly | (i) lungs |
| (b) Earthworms | (ii) gills |
| (c) Sparrow | (iii) spiracles |
| (d) Fish | (iv) skin |
Answer:
| Column I | Column II |
| (a) Butterfly | (i) Spiracles |
| (b) Earthworms | (ii) Skin |
| (c) Sparrow | (iii) Lungs |
| (d) Fish | (iv) Gills |
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