CBSE Class 11 Biology Breathing and Exchange of Gases Assignments

Question. Lungs are enclosed in
(a) periosteum
(b) perichondrium
(c) pericardium
(d) pleural membrane.
Answer. D

Question. The presence of CO₂ in blood will lower pH because CO₂ combines with____, with the rate of reaction increased by_____ . 
(a) H₂O to form H⁺ and HCO₃^–, carbonic anhydrase
(b) H₂O to form only HCO₃^–, carbonic anhydrase
(c) H₂O to form only H⁺, carbonic ions
(d) H⁺ to form HCO₃^–, oxyhaemoglobin
Answer. A

Question. Skin is an accessory organ of respiration in
(a) humans
(b) frog
(c) rabbit
(d) lizard. 
Answer. B

Question. Select the correct events that occur during inspiration.
(1) Contraction of diaphragm
(2) Contraction of external inter-costal muscles
(3) Pulmonary volume decreases
(4) Intra pulmonary pressure increases
(a) (1) and (2)
(b) (3) and (4)
(c) (1), (2) and (4)
(d) only (4) 
Answer. A

Question. Tidal volume and expiratory reserve volume of an athlete is 500 mL and 1000 mL respectively. What will be his expiratory capacity if the residual volume is 1200 mL?
(a) 2700 mL
(b) 1500 mL
(c) 1700 mL
(d) 2200 mL 
Answer. B

Question. Oxidative breakdown of respiratory substrates with the help of O₂ is called as 
(a) fermentation
(b) anaerobic respiration
(c) R. Q.
(d) aerobic respiration
Answer. D

Question. Severe Acute Respiratory Syndrome (SARS)
(a) is caused by a variant of Pneumococcus pneumoniae. 
(b) is caused by a variant of the common cold virus (corona virus).
(c) is an acute form of asthma.
(d) affects non-vegetarians much faster than the vegetarians.
Answer. B

Question. Select the correct statement.
(a) Expiration occurs due to external intercostal muscles.
(b) Intrapulmonary pressure is lower than the atmospheric pressure during inspiration.
(c) Inspiration occurs when atmospheric pressure is less than intrapulmonary pressure.
(d) Expiration is initiated due to contraction of diaphragm. 
Answer. B

Question. Match the items given in column I with those in column II and select the correct option given below.
Column I                               Column II
(A) Tidal volume               (i) 2500 – 3000 mL
(B) Inspiratory reserve      (ii) 1100 – 1200 mL volume
(C) Expiratory reserve       (iii) 500 – 550 mL volume
(D) Residual volume          (iv) 1000 – 1100 mL
(A) (B) (C) (D)
(a) (iii) (ii) (i) (iv)
(b) (iii) (i) (iv) (ii)
(c) (i) (iv) (ii) (iii)
(d) (iv) (iii) (ii) (i) 
Answer. B

Question. Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of
(a) inspiratory reserve volume
(b) tidal volume
(c) expiratory reserve volume
(d) residual volume. 
Answer. D

Question. Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because
(a) there is a negative pressure in the lungs
(b) there is a negative intrapleural pressure pulling at the lung walls
(c) there is a positive intrapleural pressure
(d) pressure in the lungs is higher than the atmospheric pressure.
Answer. B

Question. Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?
(a) One can breathe out air totally without oxygen.
(b) One can breathe out air through Eustachian tube by closing both nose and mouth.
(c) One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
(d) The lungs can be made fully empty by forcefully breathing out all air from them.
Answer. B

Question. Listed below are four respiratory capacities (i–iv) and four jumbled respiratory volumes of a normal human adult.
Respiratory capacities Respiratory volumes
(i) Residual volume 2500 mL
(ii) Vital capacity 3500 mL
(iii) Inspiratory reserve volume 1200 mL
(iv) Inspiratory capacity 4500 mL
Which one of the following is the correct matching of two capacities and volumes?
(a) (ii) 2500 mL, (iii) 4500 mL
(b) (iii) 1200 mL, (iv) 2500 mL
(c) (iv) 3500 mL, (i) 1200 mL
(d) (i) 4500 mL, (ii) 3500 mL 
Answer. C

Question. What is vital capacity of our lungs?
(a) Inspiratory reserve volume plus expiratory reserve volume
(b) Total lung capacity minus residual volume
(c) Inspiratory reserve volume plus tidal volume
(d) Total lung capacity minus expiratory reserve volume 
Answer. B

Question. Which one of the following statements is incorrect?
(a) The principle of countercurrent flow facilitates efficient respiration in gills of fishes.
(b) The residual air in lungs slightly decreases the efficiency of respiration in mammals.
(c) The presence of non-respiratory air sacs, increases the efficiency of respiration in birds.
(d) In insects, circulating body fluids serve to distribute oxygen to tissues. 
Answer. B

Question. When 1500 mL air is in the lungs, it is called
(a) residual volume
(b) inspiratory reserve volume
(c) vital capacity
(d) tidal volume. 
Answer. A

Question. The ventilation movements of the lungs in mammals are governed by
(a) muscular walls of lung
(b) diaphragm
(c) intercostal muscles
(d) both (b) and (c). 
Answer. D

Question. In man and mammals, air passes from outside into the lungs through
(a) nasal cavity, larynx, pharynx, trachea, bronchi, alveoli
(b) nasal cavity, larynx, pharynx, trachea, bronchioles, alveoli
(c) nasal cavity, pharynx, larynx, trachea, bronchioles, bronchi, alveoli
(d) nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli.
Answer. D