Respiration in Organisms Class 7 Worksheet Science Chapter 6

Q.1. True/False
(i) During heavy exercise the breathing rate of a person slows down.

False

(ii) Gills are well supplied with blood vessels for exchange of gases.

True

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

False

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

True

(v) The fishes have lungs for respiration.

False

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

True

Q.2.  Fill in the blanks.
(i)  In cockroaches, air enters the body through ____.

spiracles

(ii) During heavy exercise, we get cramps in the legs due to the accumulation of ____.

lactic acid

(iii)  Normal range of breathing rate per minute in an average adult person at rest is ____.

15ñ18

(iv) During exhalation, the ribs move ____.

downwards

(v) Breathing is a part of the process of ____.

respiration

Q.3. What forms the floor of the chest cavity?

A large, muscular sheet called diaphragm forms the floor of the chest cavity.

Q.4. What is produced during anaerobic respiration in muscles that causes cramps?

Lactic acid is produced during anaerobic respiration in muscles that causes cramps.

Q.5. Lactic acid is produced during anaerobic respiration in muscles that causes cramps.

On an average, an adult human being at rest breathes in and out 15 ñ18 times in a minute.

Q.6. What happens during exhalation?

During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs.

Q.7. When and where does anaerobic respiration occur in humans?

During heavy exercise, fast running, cycling, walking for many hours or heavy weight lifting, the demand for energy is high. But the supply of oxygen to produce the energy is limited. Then anaerobic respiration takes places in the muscle cells to fulfill the demand of energy.

Q.8. Why do we get relief from cramps after a hot water bath or a massage?

Hot water bath or massage improves circulation of blood. As a result, the supply of oxygen to the muscle cells increases. The increase in the supply of oxygen results in the complete breakdown of lactic acid into carbon dioxide and water. Thus, we get relief from cramps after a hot water bath or a massage.

Q.9. What is cell?

A cell is the smallest structural and functional unit of an organism.

Q.10. Name the respiratory organ of birds.

They have lungs in their chest cavities like the human beings.

Q.11. What are the end products of anaerobic respiration?

The end products of anaerobic respiration are alcohol, carbon dioxide and energy.

Q.12. What is cellular respiration?

The process of breakdown of food in the cell with the release of energy is called cellular respiration.

Q.13. What role does hair present in the nasal cavity play in the process of respiration?

When we inhale, the particles get trapped in the hair present in our nasal cavity. Thus, the hairs present in the nasal cavity filters the air.

Q.14. Why do we get muscle cramps after heavy exercise?

The cramps occur when muscle cells respire anaerobically. The partial breakdown of glucose produces lactic acid. The accumulation of lactic acid causes muscle cramps.

Q.15. What happens during inhalation?

During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. The lungs get filled with air.

Q.16. How does exchange of gases take place in insects?

Insects have a network of air tubes called tracheae for gas exchange. Oxygen rich air rushes through spiracles into the tracheal tubes, diffuses into the body tissue, and reaches every cell of the body. Similarly, carbon dioxide from the cells goes into the tracheal tubes and moves out through spiracles.

Q.17. What is the percentage of oxygen and carbon dioxide in inhaled and exhaled air?

When we exhale, we breathe out less oxygen but more carbon dioxide than we inhale.
Inhaled air: Oxygen 21% and Carbon dioxide 0.04%
Exhaled air: Oxygen 16.4 % and Carbon dioxide 4.4%.

Q.18. How do we breathe?

Normally we take in air through our nostrils. When we inhale air, it passes through our nostrils into the nasal cavity. From the nasal cavity, the air reaches our lungs through the windpipe. Lungs are present in the chest cavity. This cavity is surrounded by ribs on the sides. A large, muscular sheet called diaphragm forms the floor of the chest cavity. Breathing involves the movement of the diaphragm and the rib cage. During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. The lungs get filled with air. During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs.

Q.19. What are some common uses of Yeast?

Some common uses of Yeast are bread, wine and beer.

Q.20. How do earthworms breathe?

Earthworms breathe through their skins.