Class 7 Respiration in Organisms

Last updated on August 30th, 2023 at 01:02 am

Class 7 Science Chapter 10 Respiration in Organisms

Class 7 Science Chapter 10 Respiration in Organisms for CBSE/ICSE  Students.

 

QUE.1 : Why does an athlete breathe faster and deeper than usual after finishing the race?

Ans:-When an athlete runs hard, his muscles require extra energy. For this reason, he breathes faster and deeper, which allows more oxygen into his cells. As a result, food breaks down faster, releasing more energy.

 

QUE.2 : List the similarities and differences between aerobic and anaerobic respiration.

Ans:-Similarity:

During anaerobic and aerobic respiration, food is broken down to release energy.

Aerobic respiration	Anaerobic respiration
In the presence of oxygen, aerobic respiration occurs	Anaerobic respiration occurs in the absence of oxygen
CO2 and H2O are its end products.	lactic acid, CO2, and alcohol as end products.
Most organisms respire aerobically.	usually happens in most of the microbes
Complete breakdown of food occurs	Partial breakdown of food occurs
produces a considerable amount of energy	produces less energy

QUE.3 : Why do we often sneeze when we inhale a lot of dust-laden air?

Ans:-Sneezing eliminates foreign materials from the air we inhale, allowing us to breathe clean air into our bodies. It usually occurs due to irritation of the upper respiratory passage. When we inhale a lot of airborne particles and they get trapped in our nasal cavity, we get irritated. Smoke, dust and other unwanted particles can cause sneezing.

 

QUE.4 :Take three test-tubes. Fill 3/4th of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in testtube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?

Ans:-The highest concentration of CO2 will be found in test tube A. Due to the snail in test tube A. The snail breathes in O2 and exhales CO2. As a result, CO2 concentration increases in test tube A.

An oxygen-producing plant is in test tube B, which uses CO2 to produce food. In test tube B, there is a higher concentration of O2.

Both snails and plants can be found in test tube C. The snail produces CO2 which is utilized by the plant for food synthesis and the plant releases oxygen which is utilized by the snail for respiration.

Thus, test tube A has the highest concentration of CO2.

 

QUE.5 :Tick the correct answer:

(a) In cockroaches, air enters the body through

(i) lungs

(ii) gills

(iii) spiracles [Correct Answer]

(iv) skin

 

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

(i) carbon dioxide

(ii) lactic acid [Correct Answer]

(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 [Correct Answer]

(iii) 21-24

(iv) 30-33

 

(d) During exhalation, the ribs

(i) move outwards

(ii) move downwards [Correct Answer]

(iii)move upwards

(iv) do not move at all

 

QUE.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  [a]
(d) Leaves	(iv) Chest cavity
(e) Fish	(v) Stomata
(f) Frog	(vi) Lungs and skin

QUE.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. (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)

 Ans:-

1. False
2. False
3. True
4. False
5. True

 

QUE.8 :Given below is a sQue.uare 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. 

 

(i) The air tubes of insects –  Trachea

(ii) Skeletal structures surrounding chest cavity – Ribs

(iii) Muscular floor of chest cavity – 

(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 – Insects

 

QUE.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. [Correct Answer]

(c) The temperature of air is higher than that on the ground.

(d) The pressure of air is higher than that on the ground.

important points to remember

1. Respiration is the process of releasing energy from food
2. When we breathe, we take in oxygen (from the air), use it for releasing energy by burning food, and then eliminate the waste products (carbon dioxide and water) from our bodies.
3. Respiration is the opposite of photosynthesis.
4. A process by which food is broken down in cells of the body to release energy is called respiration.
5. The breakdown of glucose occurs with oxygen use, which is called aerobic respiration.
6. A method of breaking down glucose (food) in the absence of oxygen is called anaerobic respiration.
7. The yeast is a single-celled organism.
8. Yeast turns glucose into alcohol
9. Muscle cramps are caused by an accumulation of lactic acid in the muscles.
10. An organism breathes when it takes in oxygen-rich air from the environment and expels carbon dioxide-rich air from the body (using breathing organs).
11. The breathing rate is the number of times a person breathes in one minute.
12. Humans breathe on average 15 to 18 times per minute at rest.
13. According to the body’s oxygen requirements, breathing rate changes
14. Physical exercise can increase an adult human’s breathing rate by up to 25 times per minute (or more).
15. A person breathes faster when he needs extra energy.
16. During breathing, the diaphragm and rib cage move together.
17. Human respiratory system consists of: Nose, Nasal passages , Trachea, Bronchi, Lungs, and Diaphragm.
18. Gases are exchanged between the air and blood across the walls of the alveoli
19. All parts of the body receive oxygen through the blood. A red pigment called haemoglobin is responsible for carrying oxygen in red blood cells.
20. Insufficient oxygen in the body causes yawning.
21. Earthworms breathe through their skin
22. Dolphins and whales live in water, but do not have gills.
23. Whales and dolphins breathe in through their nostrils (called blowholes), which are located on the tops of their heads.
24. All insects breathe through tiny holes (called spiracles) and thin tubes (called tracheae).

 

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