Respiration in Organism - NCERT Solutions
Ques 1 - Why does an athlete breathe faster and deeper than usual after finishing the race?
Ans: When the athlete runs in the race, his body needs more oxygen. His rate of breathing increases so that more oxygen can be supplied to the body. This is the reason, an athlete needs to breathe faster and deeper than usual; after finishing the race.
Ques 2 - List the similarities and differences between aerobic and anaerobic respiration.
Ans: The similarities and differences between aerobic and anaerobic respiration are as follows:
Similarities: Food is oxidized in both cases and energy is released.
Differences: Carbon dioxide and water are the end products of aerobic respiration, while alcohol or lactic acid is the end product of anaerobic respiration. Aerobic respiration is more efficient than anaerobic respiration.
Ques 3 - Why do we often sneeze when we inhale a lot of dust-laden air?
Ans: When dust particles enter our nostril, it triggers a message to the brain. The brain instructs the nasal chamber to initiate sneezing. This is a method to remove the unwanted dust particles from the nostrils. Sneezing is a type of defense mechanism used by our body.
Ques 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?
Ans: The test tube A will have the highest concentration of carbon dioxide. The carbon dioxide comes because of respiration by the snail. In test tubes B and C; a part of the carbon dioxide is utilized by the plant for photosynthesis and hence there is less concentration of carbon dioxide.
Ques 5 - Tick the correct answer:
(a) In cockroaches, air enters the body through
Ans: (iii) Spiracles
(b) During heavy exercise, we get cramps in the legs due to the accumulation of carbon dioxide
(i) lactic acid
Ans: (i) Lactic acid
(c) Normal range of breathing rate per minute in an average adult person at rest is
Ans: (ii) 15 – 18
(d) During exhalation, the ribs
(i) move outwards
(iii) move upwards
(iv) do not move at all
Ans: (ii) Move downwards
Ques 6 - Match the items in Column I with those in Column II:
Lungs and skin
Lungs and skin
Ques 7 - Mark ‘T’ if the statement is true and ‘F’ if it is false:
1. During heavy exercise the breathing rate of a person slows down. (F)
2. Plants carry out photosynthesis only during the day and respiration only at night. (F)
3. Frogs breathe through their skins as well as their lungs. (T)
4. The fishes have lungs for respiration. (F)
5. The size of the chest cavity increases during inhalation. (T)
Ques 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 - 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
Ques 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: (b) The amount of air available to a person is less than that available on the ground