CBSE Class 11 Biology Breathing and Exchange of Gases MCQs Set E

Question. Which of the following gases makes the most stable combination with the haemoglobin of RBCs?
a) O₂
b) CO
c) CO₂
d) N
Answer: b

Question. Functional residual capacity can be represented as
a) RV + IRV
b) ERV + TV + IRV
c) ERV + RV
d) TV + ERV
Answer: c

Question. Residual air mostly occurs in
a) trachea
b) alveoli
c) bronchus
d) nostrils
Answer: b

Question. When 1200 mL air is left in the lungs, it is called
a) inspiratory reserve volume
b) tidal volume
c) residual volume
d) vital capacity
Answer: c

Question. Dissociation of oxyhaemoglobin can be promoted by
a) high blood pH
b) low pCO₂
c) high pCO₂
d) low body temperature
Answer: c

Question. In anaerobic respiration
a) O₂ is given out
b) CO₂ is given out
c) O₂ is taken in
d) CO₂ is taken in
Answer: b

Question. The volume of the air that leaves the lungs in human is measured by
a) monometer
b) spirometer
c) respirometer
d) sphygmomanometer
Answer: b

Question. What percentage of oxygen is carried by haemoglobin?
a) 23
b) 73
c) 90
d) 98
Answer: d

Question. Asthma is caused due to
a) infection of trachea
b) bleeding into pleural cavity
c) spasm in bronchial muscles
d) infection of lungs
Answer: c

Question. p50 value denotes
a) percentage of haemoglobin
b) percentage of oxyhaemoglobin
c) partial pressure of O₂
d) percentage of oxygen
Answer: c

Question. Respiratory mechanism is controlled by
a) parasympathetic nervous system
b) sympathetic nervous system
c) autonomic nervous system
d) central nervous system
Answer: d

Question. What will be the pO₂ and pCO₂ in the atmospheric air as compared to that of alveolar air?
a) Both pO₂ and pCO₂ higher
b) pO₂ higher and pCO₂ lesser
c) Both pO₂ and pCO₂ lesser
d) pO₂ lesser and pCO₂ higher
Answer: b

Question. (i) in CO₂ in your blood, which causes (ii) in pH, would cause your breathing to speed up.
a) (i) A decrease, (ii) a rise
b) (i) An increase, (ii) a rise
c) (i) A decrease, (ii) a drop
d) (i) An increase, (ii) a drop
Answer: d

Question. The pneumotaxic centre that can moderate the function of respiratory rhythm centre is located in
a) ventral side of medulla
b) dorsal side of medulla
c) pons varolii
d) aortic arch and carotid artery
Answer: c

Question. Which of the following group are supported by incomplete cartilaginous rings?
a) Pharynx, primary & tertiary bronchi and initial bronchioles
b) Trachea, primary & secondary bronchi, and initial bronchioles
c) Larynx, primary, secondary and tertiary bronchi, and initial bronchioles
d) Trachea, primary, secondary and tertiary bronchi, and initial bronchioles
Answer: d 

Statement Type Questions

Question. Identify the correct statement with reference to transport of respiratory gases by blood.
a) Only carbon dioxide is transported by blood.
b) Haemoglobin is necessary for transport of oxygen and carbonic anhydrase for transport of carbon dioxide.
c) Only oxygen is transported by blood.
d) Haemoglobin is necessary for transport of carbon dioxide and carbonic anhydrase for transport of oxygen.
Answer: b

Question. Air travels through
a) only (ii)
b) Both (i) and (ii)
c) only (i)
d) Both (i) and (iv)
Answer: d

Question. Which of the following statement is correct?
a) Expiration occurs when there is negative pressure in lungs.
b) Dorsal side of thoracic chamber is formed by sternum.
c) Tracheal rings are of hyaline cartilage.
d) All of the above
Answer: c

Question. Mark the correct statement.
a) Volume of supplementary air is lower than residual capacity.
b) Volume of complementary air is higher than tidal volume.
c) Volume of residual air is higher than tidal volume.
d) All of the above
Answer: d

Question. With reference to human respiration, which is correct?
a) Pulmonary ventilation is less than alveolar ventilation.
b) Alveolar ventilation is less than pulmonary ventilation.
c) Alveolar ventilation is more than pulmonary ventilation.
d) Pulmonary ventilation is equal to alveolar ventilation.
Answer: b

Question. Which one of the following statement is correct?
a) All animals need oxygen for respiration.
b) In all animals oxygen is transported by blood.
c) All animals require a medium for cellular respiration.
d) All of the above
Answer: c

Question. Which of the following conditions is responsible for increase in ventilation rate of lungs?
a) Decrease in O₂ content of exhaled air.
b) Increase of CO₂ content in inhaled air.
c) Decrease in O₂ content of inhaled air.
d) Increase of CO₂ content in exhaled air.
Answer: b

Question. Read the following statements and select the correct option.
(i) Carbonic anhydrase is present in the erythrocytes.
(ii) In erythrocytes the carbon dioxide combines with water and is transported.
a) Both statement (i) and (ii) are incorrect.
b) Statement (i) is correct but not involved in statement (ii).
c) Statement (i) is correct and is responsible for statement (ii).
d) Statement (i) is not correct but statement (ii) is correct.
Answer: c

Critical Thinking Type Questions

Question. The urge to inhale in humans results from
a) falling pO₂
b) rising pCO₂
c) falling pCO₂
d) rising pO₂
Answer: b

Question. Presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is
a) inefficient system of ventilation with high percentage of residual air.
b) inefficient system of ventilation with little of residual air.
c) an efficient system of ventilation with little residual air.
d) an efficient system of ventilation with no residual air.
Answer: c

Question. Common feature in the alveoli of lungs and villi of intestine in mammals is that both
a) have rich supply of blood vessels and lymph ducts.
b) are suited for diffusion of gases.
c) have ciliated epithelium.
d) provide a large surface area.
Answer: d

Question. After taking a long deep breath, we do not respire for some seconds due to
a) less O₂ in blood
b) more O₂ in blood
c) less CO₂ in blood
d) more CO₂ in blood
Answer: c

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

Question. Maximum amount of oxygen is exchanged from the blood in the
a) arteries of the body
b) left auricle of the heart
c) capillaries surrounding the alveoli
d) capillaries surrounding tissue cells
Answer: d

Question. A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues. This O₂
a) raises the pCO₂ of blood to 75 mm of Hg.
b) helps in releasing more O₂ to the epithelial tissues.
c) is enough to keep oxyhaemoglobin saturation at 96%.
d) acts as a reserve during muscular exercise.
Answer: d

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) The lungs can be made fully empty by forcefully breathing out all air from them.
c) One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
d) One can breathe out air through Eustachian tubes by closing both the nose and the mouth.
Answer: c

Question. The pharynx functions as a i, whereas the larynx functions as a ii.
a) i- passageway for air only; ii- passageway for air and food.
b) i- common passageway for air and food; ii- passageway for air only.
c) i- block to bacteria; ii- passage for air and food.
d) i- common passage for air and food; ii- passageway for food only.
Answer: b

Question. The chloride shift in red blood cells is the movement of
a) chloride ions from the blood into the glomerular filtrate for excretion.
b) chloride ions into the cell to balance its uptake of hydrogencarbonate ions.
c) cations into the cell to balance its uptake of chloride ions.
d) chloride ions out of the cell to balance the release of hydrogencarbonate ions.
Answer: d

Question. External gills, tracheae, and lungs all share which of the following sets of characteristics?
a) Used by water breathers; based on countercurrent exchange; use negative pressure breathing.
b) Exchange only O₂; are associated with a circulatory system; found in vertebrates.
c) Found in insects; employ positive-pressure pumping based on crosscurrent flow.
d) Part of gas-exchange system, exchange both CO₂ and O₂; increase surface area for diffusion.
Answer: d