Respiration in Organisms Chapter 6 Class 7 Important Questions

In this page we have Respiration in Organisms Important Questions for Class 7 Science . Hope you like them and do not forget to like , social share and comment at the end of the page.

Fill in the blanks

Question 1
i. ___________ and ___________ are two by-products of respiration.
ii. Lactic acid is also called as __________
iii. Yeast breaks down glucose into ____________ and carbon di-oxide.
iv. The accumulation of ____________ causes muscle cramps.
vi. The____________ is a tube-like structure present in human respiratory system and is commonly known as wind pipe.
vii. ___________ is the muscular partition which between chest and abdominal cavity.
ix. Frogs breathe both by ___________ and __________
x. Plants get oxygen by the process of ____________
xi. Amoeba breathes through its ________


  1. Carbon dioxide, water
  2. Lactate or milk acid
  3. Alcohol
  4. Lactic acid
  5. Alveoli
  6. Trachea
  7. Diaphragm
  8. Nitrogen
  9. Lungs and moist skin
  10. Diffusion
  11. Cell membrane

Question 2
a. ________ is utilised during respiration to release energy.
b. ________ gas is released when human beings respire.
c. ________ is not required for anaerobic respiration.
d.The air in the alveoli is called ________ air.
e.Below the rib cage there is a sheet of muscles called the ________.
f.In earthworm, the exchange of gases takes place through the ________.
g.Gaseous exchange takes place in butterflies through ________.
h.The ________ is commonly called the windpipe.
i.Fish respire through ________.
j.Respiration through the skin is called ________.
k.Anaerobic respiration produces ________.
l. ________ transport oxygen to every part of the body.
m.In blood a pigment called ________ bind with oxygen.
n.Muscle cramps occur due to accumulation of ________ in the muscles.
o.In most vertebrates gaseous exchange occurs through ________.
p.During ________ the lungs contract.
q.Anaerobic respiration in human beings takes place during ________.
r.The breakdown of food in cells using oxygen with the release of energy is called ________.
s.________ turns limewater milky.
t.The exchange of gases in the leaves of plants takes place through ________.


a. Glucose
b. Carbon dioxide
f.Moist skin
j.cutaneous respiration.
n.lactic acid
q.rigorous exercise
r.aerobic respiration
s.Carbon dioxide

Very short answer questions

Question 3
i. Name the term used for openings in the nose
ii. What name is given to the part of trachea entering in the lungs?
iii. Name the organs through which insects take in air
iv. Which is the breathing organ in unicellular organisms?
v. Which organ extracts dissolved oxygen from water in fishes?
vi. Name the term used for one inhalation plus one exhalation.
vii. Which special organs are found only in insects and not in any other group of animals?
viii. Where does exchange of gases take place in lungs?
ix. What ATP stands for?


  1. Nostrils
  2. Bronchi
  3. Spiracles
  4. Cell membrane
  5. Gills
  6. Breathe
  7. Tracheae
  8. Alveoli
  9. Adenosine Tri-Phosphate

Multiple Choice Questions

Question 4
Yeast is used in wine and beer industries because it respires
(a) aerobically producing oxygen.
(b) aerobically producing alcohol.
(c) anaerobically producing alcohol.
(d) anaerobically producing CO2.

Question 5
During the process of exhalation, the ribs move
(a) down and inwards.
(b) up and inwards.
(c) down and outwards.
(d) up and outward.

Question 6
Earthworms and frogs breathe through their skin because of
which the skin of both the organisms is
(a) moist and rough.
(b) dry and rough.
(c) dry and slimy.
(d) moist and slimy.

Question 7
Fish breathe with the help of gills which are richly supplied with blood vessels. The gills help the fish to
(a) take in oxygen from air.
(b) release waste substances in water
(c) absorb nutrients present in water.
(d) take in oxygen dissolved in water.


4. (c)
5. (a)
6. (d)
7. (d)

Crossword Puzzle

Question 8

2. The process of breakdown of food in the cell with the release of energy is called ______respiration
5. The taking in of air rich in oxygen into the body is called _______
1. The process of giving out of air rich in carbon dioxide is known as _____
3. respiration with oxygen
4. They are single-celled organisms.
6. respiration without oxygen


  1. exhalation
  2. cellular
  3. aerobic
  4. Yeasts
  5. Inhalation
  6. Anaerobic

Jumbled word

Question 9
Unscramble the Jumbled word


  1. Diaphragm
  2. Tracheae
  3. Oxygen
  4. Glucose
  5. Respiration

Short Answer type Questions

Question 10
Give reasons why-
i. The amount of nitrogen gas remains same in inhaled and exhaled air.
ii. Fishes die when they are taken out of water.
iii. Carbon monoxide is a harmful gas.
iv. Mountaineers carry oxygen cylinder with them.
Question 11
Why do we feel hungry after the physical activity?
Question 12
Why do you breathe through nose and not through mouth?
Question 13
Why does lime water turn milky when we blow into it?
Question 14
Differentiate between breathing and respiration.
Question 15
Explain the mechanism of breathing in human beings through a flowchart.

Question 16
What is breathing?

Question 17
What is cellular respiration?

Question 18
What is the role of stomata in plant cells?

Question 19
In which body part does gaseous exchange occur in fish?

Question 20
What is breathing rate?

Question 21
What is respiration without oxygen called? How do plants take in air?

Question 22
Describe gaseous exchange in the human body?

Question 23
Differentiate between inhalation and exhalation?

Question 24
Describe how inhalation and exhalation takes place in the human respiratory system?

Question 25
Name the structures of the human respiratory system and write their functions starting from the organ through which the air enters?

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