NCERT Solutions for Chapter 10 Respiration in Organisms Class 7 Science
Book Solutions1
Answer
During the run, the demand of energy is high but the supply of oxygen to produce energy is limited. Therefore, anaerobic respiration takes places in the muscle cells to fulfill the demand of energy. After finishing the race, an athlete breathe faster and deeper than usual so that more oxygen is supplied to the cells.2
Answer
Similarity:
(i) In both aerobic and anaerobic respiration, food is broken down to release energy.
(ii) Both takes place inside cells.
(iii) Both produces byproducts.
Differences:
|
Aerobic Respiration |
Anaerobic Respiration |
|
(i) It takes place in the presence of oxygen. |
(i) It takes place in the absence of oxygen. |
|
(ii) Energy is released in higher amount. |
(ii) Energy is released in lesser amount. |
|
(iii) Carbon dioxide and water are produced as byproducts. |
(iii) Carbon dioxide and water are produced as byproducts. |
|
(iv) It is a slow process. |
(iv) It is a fast process. |
|
(v) Examples: Animals and plants cells. |
(iv) Examples: Human cells, yeast, Bacteria etc. |
3
Answer
We often sneeze when we inhale a lot of dust-laden air to expel out these foreign particles. These particles get past the hair in the nasal cavity and irritate the lining of the cavity which results in sneezing.4
Take three test-tubes. Fill
each of them 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 ?
Answer
Test-tube A will have the highest concentration of CO2 because snail will take in oxygen and gives out CO2.
In test-tubes B and C, the CO2 will be utilized by the water plant for synthesizing food and hence there will be less concentration of CO2 in these.
5
(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
Answer
(b)✓ (ii) lactic acid
(c)✓ (ii) 15 - 18
(d)✓ (ii) move downwards
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) Leaves |
(iv) Chest cavity |
|
(e) Fish |
(v) Stomata |
|
(f) Frog |
(vi) Lungs and skin |
|
- |
(vii) Tracheae |
Answer
|
Column I |
Column II |
|
(a) Yeast |
(iii) Alcohol |
|
(b) Diaphragm |
(iv) Chest cavity |
|
(c) Skin |
(i) Earthworm |
|
(d) Leaves |
(v) Stomata |
|
(e) Fish |
(ii) Gills |
|
(f) Frog |
(vi) Lungs and skin |
7
Answer
(ii) F
(iii) T
(iv) F
(v) T
8
Answer
(i) The air tubes of insects → Trachea
(ii) Skeletal structures surrounding chest cavity → Ribs
(iii) Muscular floor of chest cavity → Diaphragm
(iv) Tiny pores on the surface of leaf → Stomata
(v) Small openings on the sides of the body of an insect → Spiracles
(vi) The respiratory organs of human beings → Lungs
(vii) The openings through which we inhale → Nostrils
(viii) An anaerobic organism → Yeast
(ix) An organism with tracheal system → Ant
9
Answer
The mountaineers carry oxygen with them because (b) The amount of air available to a person is less than that available on the ground.