In This Post we are providing Chapter-17 Breathing and Exchange of Gases NCERT MCQ for Class 11 Biology which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.
NCERT MCQ ON BREATHING AND EXCHANGE OF GASES
Question 1 : When CO2 concentration in blood increases, breathing becomes
- a) faster and deeper
- b) slow and deep
- c) there is no effect on breathing
- d) shallower and slow
Answer : faster and deeper
Question 2 : The largest quantity of air that can be expired after a maximal inspiratory effort is called
- a) vital capacity
- b) residual volume
- c) tidal volume
- d) total lung volume
Answer : vital capacity
Question 3 : Which one of the following statements is incorrect ?
- a) In insects, circulating body fluids serve to distribute oxygen to tissues
- b) The principle of counter current flow facilitates efficient respiration in gills of fishes
- c) The residual air in lungs slightly decreases the efficiency of respriration in mammals.
- d) None of these
Answer : In insects, circulating body fluids serve to distribute oxygen to tissues
Question 4 : Emphysema develops mainly because of
- a) Spasm of the smooth muscles of bronchioles
- b) Cigarette smoking
- c) Inflammation of the alveoli
- d) Allergy or hypersensitisation
Answer : Spasm of the smooth muscles of bronchioles
Question 5 : During inspiration the diaphragm
- a) contracts and flattens
- b) relaxes to become dome-shaped
- c) shows no change
- d) None of these
Answer : contracts and flattens
Question 6 : The volume of air breathed in and out during normal breathing is called
- a) Tidal volume
- b) Explratory reserve volume
- c) Vital capacity
- d) None of these
Answer : Tidal volume
Question 7 : What would happen if human blood becomes acidic (low pH)
- a) Oxygen carrying capacity of haemoglobin decreases
- b) RBCs count increases
- c) RBCs count decreases
- d) Oxygen carying capacity of haemoglobin increases
Answer : Oxygen carrying capacity of hemoglobin decreases
Question 8 : Even when there is no air in it, human trachea does not collapse due to presence of
- a) Cartilaginous rings
- b) Turgid pressure
- c) Bony rings
- d) Chitinous rings
Answer : Cartilaginous rings
Question 9 : The structure which does not contribute to the breathing movements in mammals is
- a) Larynx
- b) Diaphragm
- c) Ribs
- d) Intercostal muscles
Answer : Larynx
Question 10 : In emphysema
- a) Gas exchange area of lungs is reduced
- b) Gas exchange area of lungs is increased
- c) Trachea gets narrowed
- d) Larynx is permanently closed
Answer : Gas exchange area of lungs is reduced
Question 11 : Which of the following changes occur in diaphragm and intercostal muscles when expiration of air takes place?
- a) External intercostal muscles and diaphargm relax
- b) External intercostal muscles and diaphargm contract
- c) External intercostal muscles contract and diaphargm relaxes
- d) External intercostal muscles relax and diaphargm contracts
Answer : External intercostal muscles and diaphragm relax
Question 12 : When you exhale, the diaphragm
- a) relaxes and arches
- b) relaxes and flattens.
- c) contracts and arches
- d) contracts and flattens
Answer : relaxes and arches
Question 13 : Smoking destroys the cilia in the respiratory passageways. This
- a) makes it harder to keep the lungs clean
- b) slows blood flow through lung blood vessels
- c) decreases the surface area for respiration.
- d) makes it harder to move air in and out of the lungs
Answer : makes it harder to keep the lungs clean
Question 14: Gas flows into the lungs of mammals during inspiration because
- a) The pressure in the lungs falls below atmospheric pressure
- b) The pressure in the lungs rises above atmospheric pressure.
- c) The volume of the lungs decreases
- d) The diaphragm moves upward toward the lungs
Answer : The pressure in the lungs falls below atmospheric pressure
Question 15 : The function of the mucus elevator in the mammalian respiratory system is to
- a) trap and remove particulate matter that has entered the respiratory system.
- b) stimulate contraction of rib musculature during forcible exhalation
- c) produce negative pressure during inhalation
- d) move surfactant from the bronchi to the alveoli
Answer : trap and remove particulate matter that has entered the respiratory system.
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