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Class seven science NCERT Solutions Respiration in Organisms
Chapter 10: Respiration in Organisms
Respiration in Organisms
N C E R T Questions
Q1. Why does an athlete breathe faster and deeper than usual after finishing the race?
Answer While running, the demand for energy in the body increases, but the supply of oxygen to produce energy is limited. So to fulfil this demand, an athlete breathes faster and deeper than usual to breathe more oxygen that can be supplied in more quantity to the cells for producing more energy.
Q2. List the similarities and differences between aerobic and anaerobic respiration.
(i) In both aerobic and anaerobic respiration,
food is broken down to release energy.
(ii) Both take place inside cells.
(iii) Both produce by-products.
Q3. Why do we often sneeze when we inhale a lot of dust-laden air?
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.
Q4. 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 synthesising food and hence there will be less concentration of CO2 in these.
Q5. Tick the correct answer:
(a) In cockroaches, air enters the body through
Answer (iii) spiracles
(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide (iii) alcohol
(ii) lactic acid (iv) water
Answers (ii) lactic acid
(c) The normal range of breathing rate per minute in an average adult person at
i 9 – 12.
ii 15 – 18
iii 21 – 24
iv 30 – 33
Answers (ii) 15 – 18
(d) During exhalation, the ribs:
i move outwards
ii move downwards
iii moves upwards
iv do not move at all
Answers (ii) move downwards
Q6. Match the items in Column I with those in
Q7. 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)
Answers (i) F (ii) F (iii) T (iv) F (v) T
Q8. 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 the chest cavity
(iii) The muscular floor of the chest cavity
(iv) Tiny pores on the surface of the 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 a tracheal system
(i) The air tubes of insects → Trachea
(ii) Skeletal structures surrounding chest cavity → Ribs
(iii) The 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 a tracheal system → Ant
Q9. 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 the air is higher than that on the ground.
(d) The pressure of air is higher than that on the ground.
The mountaineers carry oxygen with them because (b) The amount of air available to a person is less than that available on the ground.