Chapter 10, Respiration in Organisms| Class 7 |Science| NCERT Solutions
Question 1. Why does an athlete breathe faster and deeper than usual after finishing the race?
Answer 1 When an athlete runs in the race, his body needs lots of energy.
2. List the similarities and differences between aerobic and anaerobic respiration.
Answer 2 Similarity between aerobic and anaerobic respiration
1) Food is oxidised in both the cases.
2) Both takes place inside cell.
3) Both produces by products.
Difference between aerobic and anaerobic respiration
|Aerobic Respiration||Anaerobic respiration|
|It takes place in the presence of oxygen||It takes place in the absence of oxygen.|
|End products are Carbon dioxide and water||End products are ethyl alcohol or lactic acid and Carbon dioxide.|
|Energy released is in larger amount.||Energy is released in lesser amount.|
|It occurs in plant and animal cells||It occurs in human muscle cells, anaerobic bacteria.|
3. Why do we often sneeze when we inhale a lot of dust-laden air?
4. Take three test-tubes. Fill ¾th of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?
5. Tick the correct answer:
(a) In cockroaches, air enters the body through
(i) lungs (ii) gills (iii) spiracles (iv) skin
(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide (ii) lactic acid (iii) alcohol (iv) water
(c) Normal range of breathing rate per minute in an average adult person at rest is:
(i) 9–12 (ii) 15–18 (iii) 21–24 (iv) 30–33
(d) During exhalation, the ribs
(i) move outwards (ii) move downwards (iii) move upwards (iv) do not move at all
6. Match the items in Column I with those in Column II:
Column I Column II
(a) Yeast (i) Earthworm
(b) Diaphragm (ii) Gills
(c) Skin (iii) Alcohol
(d) Leave (iv) Chest cavity
(e) Fish (v) Stomata
(f) Frog (vi) Lungs and skin
7. Mark ‘T’ if the statement is true and ‘F’ if it is false
: (i) During heavy exercise the breathing rate of a person slows down. (T/F)
(ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F)
(iii) Frogs breathe through their skins as well as their lungs. (T/F)
(iv) The fishes have lungs for respiration. (T/F)
(v) The size of the chest cavity increases during inhalation. (T/F)
8. Given below is a square of letters in which are hidden different words related to respiration in organisms. These words may be present in any direction — upwards, downwards, or along the diagonals. Find the words for your respiratory system. Clues about those words are given below the square.
(i) The air tubes of insects
(ii) Skeletal structures surrounding chest cavity
(iii) Muscular floor of chest cavity
(iv) Tiny pores on the surface of leaf
(v) Small openings on the sides of the body of an insect
(vi) The respiratory organs of human beings
(vii) The openings through which we inhale
(viii) An anaerobic organism
(ix) An organism with tracheal system
9. The mountaineers carry oxygen with them because:
(a) At an altitude of more than 5 km there is no air.
(b) The amount of air available to a person is less than that available on the ground.
(c) The temperature of air is higher than that on the ground.
(d) The pressure of air is higher than that on the ground.