MCQ on Respiration in Organisms

CBSE/NCERT 7th Class MCQ CBSE/NCERT 7th Class MCQ on Science

MCQ on Respiration in Organisms

1. All organisms are made of small microscopic units called

(A) Cells

(B) Tissues

(C) Atom

(D) None of the above


 2. A cell is the smallest structural and functional unit of a/an ………………….

(A) Organism

(B) Tissue

(C) Stomata

(D) None of the above


3. Which of the following option is a function performed by a cell in an organism?

(A) Nutrition

(B) Transportation

(C) Excretion and Reproduction

(D) All of the above


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

(A) Aerobic respiration

(B) Cellular respiration

(C) Anaerobic respiration

(D) None of the above


5.……………. respiration takes place in the cells of all organisms.

(A) Anaerobic

(B) Aerobic

(C) Cellular

(D) All of the above


6.Breakdown of glucose within the cell with the use of oxygen it is called ……….

(A) Aerobic respiration

(B) Anaerobic respiration

(C) Cellular respiration

(D) All of the above


7.Breakdown of food without using oxygen within a cell it is called …………

(A) Excretion

(B) Aerobic

(C) Cellular

(D) Anaerobic


8.Complete the equation

Glucose in absence of Oxygen releases à

(A) carbon dioxide + water + energy

(B) alcohol + energy

(C) water + energy

(D) None of the above


9.…………..organism can survive in the absence of air. They are called

(A) Yeast

(B) Tapeworm

(C) Both A and B

(D) None of the above


10. In absence of air or oxygen, glucose breaks down into

(A) energy + alcohol

(B) alcohol + carbon dioxide

(C) carbon dioxide + energy

(D) alcohol + carbon dioxide + energy



  1. (A) 2. (A) 3.(D)       4. (B)         5.(C)           6.(A)        7. (D )        8.(A)       9. (C)      10. (D)     


11. Yeast a single celled organism are used to make 

(A) Beer

(B) Wine

(C) Medicine

(D) Both A and B


12. During heavy exercise, fast running, cycling, walking for many hours or heavy weight lifting the demand for energy by our body is high. In this what type of respiration takes place

(A) Aerobic respiration

(B) Anaerobic respiration

(C) Cellular respiration

(D) None of the above


13. Glucose (in muscles) in the absence of oxygen respire

(A) Acidic +energy

(B) Energy

(C) Lactic acid + energy

(D) None of the above


14. The partial breakdown of glucose produce …………………

(A) Lactic acid

(B) Acetic acid

(C) Formic acid

(D) Hydrochloric acid


15. The accumulation of lactic acid causes muscles ………………

(A) Pain

(B) Cramps

(C) Bone damage

(D) None of the above


16.………………..means taking in air rich in oxygen and giving out air rich in carbon dioxide with help of respiratory organs

(A) Breathing

(B) Inhalation

(C) Exhalation

(D) All of the above


17. Taking in of air rich in oxygen into the body is called

(A) Inhalation

(B) Exhalation

(C) Respiration

(D) Excretion


18. Giving out of air rich in carbon dioxide is known as

(A) Respiration

(B) Exhalation

(C) Inhalation

(D) None of the above


19. Number of times a person breathes in a minute is termed as the ………..

(A) Breathing rate

(B) Breathing minute

(C) Pulse Rate

(D) None of the above


20. Average breathing rate at rest in a minute in normal a human body …………

(A) 10 times in a minute

(B) 25 times in a minute

(C) 15-18 times in a minute

(D) 25-30 times in a minute



  1. (D) 12. (B) 13. ( C)     14. (A)         15. (B)    16.( A)        17. (A)      18. (B)       19. (A)      20. (C)


21. During heavy exercise, breath rate increases upto

(A) 15-20 times per minute

(B) 25 times per minute

(C) 30-35 times per minute

(D) 50 times per minute


22. We inhale air through our ………….

(A) Chest

(B) Lungs

(C) Nostrils

(D) Diaphragm


23. Air passes through our nostrils into the ………………..

(A) Rib cage

(B) Diaphragm

(C) Nasal cavity

(D) None of the above


24. From nasal cavity the air reaches our …………………through the windpipe.

(A) Lungs

(B) Heart

(C) Nostrils

(D) Diaphragm


25.………..present in the chest cavity surrounded by ribs on the sides.

(A) Lungs

(B) Intestine

(C) Windpipe

(D) Heart


26.……………..forms the floor of the chest cavity.

(A) Intestine

(B) Diaphragm

(C) Chest

(D) Excretion


27………..damages lungs and linked to cancer.

(A) Exercise

(B) Fast food

(C) Drinking water

(D) Smoking


28. Unwanted particles like dust, smoke and pollen etc get trapped by the……………. present in our nasal cavity.

(A) Hair

(B) Veins

(C) Air

(D) Nasal lining


29. What statement if correct regarding the percentage of oxygen and carbon dioxide when we inhale?

  • (a) The percentage of oxygen in inhaled by our body is 21% and by lungs is 0.04% carbon dioxide.
  • (b) The percentage of oxygen exhaled by our body is 16.4% and by lungs is 4.4% carbon dioxide.

(A) Option (a) and (b)

(B) Option (a)

(C) Option (b)

(D) None of the above


30. Small opening on the sides of the cockroach body for breathing are called

(A) Tracheae

(B) Spiracles

(C) Both A and B

(D) None of the above



21.(B)    22.(C)      23.(C)       24.(A)       25.(A)        26.(B)        27.(D)       28.(A)       29.(A)      30.(B)


31. Network of air tubes for gas exchanges in cockroaches are called

(A) Spiral

(B) Chest cavity

(C) Tracheae

(D) None of the above


32. ………. Breathe through their skins.

(A) Fish

(B) Earthworms

(C) Cockroach

(D) All of the above


33. ………….in fish helps them to use oxygen dissolved in water.

(A) Nostrils

(B) Chest

(C) Gills

(D) Heart


34. Tiny pores in leaves of a plant are called …………….

(A) Stomata

(B) Guard

(C)  Both A and B

(D) None of the above


35. In cells ……………is used to breakdown glucose into carbon dioxide and water.

(A) Nitrogen

(B) Argon

(C) Oxygen

(D) All of the above


36. …………….is essential for survival of living organisms. It releases energy from the food.

(A) Respiration

(B) Expiration


37. During inhalation, our lungs expand and then comes back to the original state as air moves out during Exhalation.

Is this statement being true or false.

(A) True

(B) False


38. Which of the following statement is correct?

  • (a) Earthworms, exchange of gases occurs through the moist skin.
  • (b) Fishes takes oxygen dissolved in water through gills.
  • (c) Insects exchange oxygen through the tracheae.

(A) Option (b) only

(B) Option (c) only

(C) Option (a), (b), (c)

(D) None of the above


39. In a cockroach, air enters the body through

(A) Spiracles

(B) Lungs

(C) Gills

(D) Skin


40.During heavy exercise, we get cramps in the legs due to the accumulation of

(A) Oxygen

(B) Water

(C) Carbon dioxide

(D) Lactic acid



31.(C)      32.(B)   33.(C)       34.(A)       35.(C)         36.(A)         37. (A)         38.(C)       39.(A)       40.(D)


41. During Exhalation, the ribs move

(A) Upwards

(B) Downwards

(C) Outwards

(D) No movements


42. Match the following

List I                                       List II

  1. Yeast                          a. Earthworm
  2. Diaphragm                 b. Gills
  3. Skin                            c. Alcohol
  4. Leaves                        d. Chest cavity
  5. Fish                             e. Stomata                          


(A) 1-c      2-d        3-a       4-e         5-b         

(B) 1-a     2-b        3-c       4-d       5-e      



41.(A)     42.(A)