Respiration in Organisms (NCERT Solutions,Class 7)

(1) Why does an athlete breathe faster and deeper than usual after finishing the race?Ans-   After running fast an athlete breathe faster and deeper than usual because the supply of oxygen temporary deficient. He breathes deep and fast to take more oxygen that is needed to break carbohydrate and release energy.

(2) List the similarities and differences between aerobic and anaerobic respiration.

  Differences between aerobic and anaerobic respiration are given below:

S.N. Aerobic respiration Anaerobic respiration
1. The processes when breakdown of glucose occurs with the use of oxygen The processes when breakdown of glucose occurs without using oxygen
2. Breakdown of the food releases water, carbon dioxide and energy Breakdown of the food releases alcohol, carbon dioxide and energy
3. It takes large time to release energy It takes less time to release energy.
4. Eg:- plants and animals Eg:- yeast

Similarities between aerobic and anaerobic respiration are given below:-

S.N. Aerobic respiration Anaerobic respiration
1. Process of respiration Process of respiration
2. Releases energy and carbon dioxide Releases energy and carbon dioxide

 (3) Why do we often sneeze when we inhale a lot of dust- laden air?

Ans- When we inhale dust its particles prevented by hair in our nose to enter into the nose. But, sometimes some particle gets into the nasal cavity. It irritates inside the nose. As a result of it we sneeze a lot. Our sneezing ejects dust particles out from the nose. We feel comfortable and can inhale fresh air.

(4) Take three test tubes. Fill ¾ 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 water plant both. Which test- tube would have the highest concentration of C02?

Ans-

Test tube A:-  Snail is an animal which inhales oxygen and exhale carbon dioxide. Hence, in test tube A concentration of oxygen will decline and the concentration of CO2 will increase.

Test tube B:- A water plant inhales carbon dioxide and releases oxygen. So, in test tube B concentration of oxygen will increase and the concentration of CO2 will decrease.

Test tube C:- Snail inhales oxygen and exhales carbon dioxide. So concentration of CO2 will increase. But water plant takes carbon dioxide and releases oxygen. Hence concentration of oxygen will increase.

Hence, test tube A has 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

Ans-

(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) Leaves                                                                              (iv) Chest cavity

(e) Fish                                                                                   (v) Stomata

(f) Frog                                                                                   (vi) Lungs and skin

(vii) Tracheae

Ans-

(a) – (iii)

(b)-  (iv)

(c) – (i)

(d) – (v)

(e) – (ii)

(f) – (vi)

(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.

(ii) Plants carry out photosynthesis only during the day and respiration only at night.

(ii) Frogs breathe through their skins as well as their lungs.

(iv) The fishes have lungs for respiration.

(v) The size of the chest cavity increases during inhalation.  

Ans-

(i) During heavy exercise the breathing rate of a person slows down.   F

(ii) Plants carry out photosynthesis only during the day and respiration only at night.   F

(ii) Frogs breathe through their skins as well as their lungs. T

(iv) The fishes have lungs for respiration.    F

(v) The size of the chest cavity increases during inhalation.   T

(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.

Respiration in organisms,Q 8,NCERT,class 7

(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 begins

(vii) The openings through which we inhale

(viii) An anaerobic organism

(ix) An organism with tracheal system

Ans- Words for the respiratory system is shown below in the square.

Respiration in organisms,A 8,NCERT,class 7

(i) Trachea

(ii)Ribs

(iii) Diaphragm

(iv)Stomata

(v)Spircales

(vi)Lungs

(vii) Nostrils

(viii)Ant

(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.

Ans-

(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.

Helping Topics

Respiration in organisms

Practice sheet

Why does an athlete breathe faster and deeper than usual after finishing the race?

List the similarities and differences between aerobic and anaerobic respiration.

 

warning-blog

Leave a comment