NEET Biology Multiple Choice Questions – Breathing And Exchange Of Gases

Breathing And Exchange Of Gases Multiple Choice Question And Answers

Question 1. Which of the following structures is not supported by incomplete cartilaginous rings?

1. Trachea
2. Secondary bronchi
3. Terminal bronchioles
4. Primary bronchi

Answer: 3. Trachea

Question 2. Teacher is a straight tube extending up to the mid-thoracic cavity, which divides at the level of

1. Second cervical vertebra
2. Fifth cervical vertebra
3. Fifth thoracic vertebra
4. Fifth lumbar vertebra

Answer: 3. Fifth thoracic vertebra

Question 3. The outer pleural membrane is in close contact with

1. Surface of lungs
2. Thoracic cavity
3. Both (1) and (2)
4. Alveoli.

Answer: 2. Thoracic cavity

Question 4. The volume of air remaining in the lungs even after a forcible expiration is

1. Expiratory reserve volume
2. Expiratory capacity
3. Residual volume
4. Both (1) and (2)

Answer: 3. Residual volume

Question 5. The maximum volume of air a person can breathe in after a forced expiration is

1. Vital capacity
2. ERV + TV + JRV
3. TLC + RV
4. All of these

Answer: 4. All of these

Question 6. Which of the following statements is incorrect w.r.t. the mechanism of breathing?

1. The movement of air into and out of the lungs is carried out by creating a pressure gradient between the lungs and the atmosphere.
2. Inspiration is initiated by the contraction of the diaphragm which increases the volume of the thoracic chamber.
3. The contraction of external intercostal muscles lifts up the ribs and sternum causing a decrease in the volume of the thoracic chamber.
4. On average, a healthy human breathes 12-16 times/ min.

Answer: 3. The contraction of external intercostal muscles lifts up the ribs and sternum causing a decrease in the volume of the thoracic chamber.

Question 7. The thoracic cage of man is formed of

1. Ribs and sternum
2. Ribs, sternum, and thoracic vertebrae
3. Ribs, sternum, and lumbar vertebrae
4. Ribs and thoracic vertebrae

Answer: 2. Ribs, sternum, and thoracic vertebrae

Question 8. The Trachea is lined with incomplete rings of

1. Fibrous cartilage
2. Calcified cartilage
3. Elastic cartilage
4. Hyaline cartilage

Answer: 4. Hyaline cartilage

Question 9. Lungs have a large number of alveoli for

1. Having a spongy texture and proper shape
2. More surface area for diffusion of gases
3. More space for increasing the volume of inspired air
4. More nerve supply

Answer: 2. More surface area for diffusion of gases

Question 10. In mammals, ventilation movements of the lungs are governed by

1. Muscular wall of lungs
2. Intercostal muscles
3. Diaphragm
4. Diaphragm and intercostal muscles

Answer: 4. Diaphragm and intercostal muscles

Question 11. What will be the po₂ and pco₂ in the atmospheric air as compared to those in the alveolar air?

1. Po₂ lesser, pco₂ higher
2. Po₂ higher, pco₂ lesser
3. Po₂ higher, pco₂ higher
4. Po₂ lesser, pco₂ lesser

Answer: 2. po₂ higher, pco₂ lesser

Question 12. What is the partial pressure of oxygen and carbon dioxide in atmospheric air?

1. Po₂ 159 mm Hg,pco₂0.3 mm Hg
2. Po₂ 104 mm Hg, pco₂ 40 mm Hg
3. Po₂ 40 mm Hg,pCo₂45 mm Hg
4. Po₂ 95 mm Hg,/>Co₂ 40 mm Hg

Answer: 1. po2 159 mm Hg,pco₂0.3 mm Hg

Question 13. Diffusion membrane is made up of which of the following layers?

1. Thin squamous epithelium of alveoli
2. Basement membrane
3. Endothelium of alveolar capillaries
4. All of these

Answer: 4. All of these

Question 14. Which of the following statements is incorrect about the transport of gases?

1. About 97% of O₂ is transported by RBCs in the blood.
2. About 3% of O₂ is carried in a dissolved state in the plasma.
3. About 20-25% of CO₂ is transported by RBCs.
4. About 70% of carbon dioxide is carried in a dissolved state in plasma.

Answer: 4. About 70% of carbon dioxide is carried in a dissolved state in plasma.

Question 15. The binding of oxygen with hemoglobin is primarily related to which of the following factors?

1. Partial pressure of CO₂
2. Partial pressure of O₂
3. Hydrogen ion concentration
4. Temperature

Answer: 2. Partial pressure of O₂

Question 16. Which of the following factors are favorable for the formation of oxyhemoglobin?

1. High po₂, low pco₂

2. Lesser H1 concentration, lower temperature

3. Low Po₂, high CO₂

4. High Hf, higher temperature

1. 1 only
2. 1 and 2
3. 2 and 3
4. 3 and 4

Answer: 2. 1 and 2

Question 17. Under which conditions the oxygen dissociation curve will move towards the right?

1. Low po₂
2. High Co₂
3. High H⁺ concentration and higher temperature
4. All of these

Answer: 4. All of these

Question 18. Tick mark the incorrect statement.

1. Every 100 mL of deoxygenated blood delivers approximately 4 mL of CO₂ to the alveoli.
2. Carbonic anhydrase is present in very high concentrations in RBC.
3. High pco₂ and low po₂ in tissues help in the binding of carbon dioxide.
4. CO₂ is carried in hemoglobin as carboxyhemoglobin.

Answer: 4. CO₂ is carried in hemoglobin as carboxyhemoglobin.

Question 19. Carbon dioxide is carried in the blood mainly as

1. Sodium bicarbonate
2. Potassium bicarbonate
3. Carbamino-hemoglobin
4. Dissolved gas in plasma

Answer: 1. Sodium bicarbonate

Question 20.The hemoglobin of a human fetus

1. Has higher affinity for oxygen than that of an adult
2. Has a lower affinity for oxygen than that of an adult
3. Has the same affinity for oxygen as an adult
4. Has two protein sub-units instead of four

Answer: 1. Has a higher affinity for oxygen than that of an adult

Question 21. Ring-like cartilage of the larynx is known as

1. Thyroid cartilage
2. Arytenoid cartilage
3. Cricoid cartilage
4. Cartilage of Santorini

Answer: 3. Cricoid cartilage

Question 22. Which of the following prevents the collapsing of the trachea?

1. Muscles
2. Diaphragm
3. Ribs
4. Cartilaginous rings

Answer: 4. Cartilaginous rings

Question 23. The trachea is lined with incomplete rings of

1. Fibrous cartilage
2. Calcified cartilage
3. Elastic cartilage
4. Hyaline cartilage

Answer: 4. Hyaline cartilage

Question 24. The number of alveoli in the human lungs has been estimated to be approximately

1. 100 million
2. 300 million
3. 125 million
4. 300 billion

Answer: 2. 300 million

Question 25. In humans, the oblique fissure is present in

1. Right lung
2. Left lung
3. Both of these
4. None of these

Answer: 3. Both of these

Question 26. The covering of the lung is called

1. Pericardium
2. Perichondrium
3. Pleural membrane
4. Peritoneum

Answer: 3. Pleural membrane

Question 27. The terminal bronchiole is lined by

1. Simple squamous epithelium
2. Ciliated columnar or cuboidal epithelium
3. Stratified epithelium
4. Pseudostratified epithelium

Answer: 2. Ciliated columnar or cuboidal epithelium

Question 28. Which of the following muscles contracts during normal expiration?

1. Internal intercostal muscles
2. Diaphragm
3. Abdominal muscles
4. None of these

Answer: 4. None of these

Question 29. Chest movements are inconspicuous during

1. Normal breathing
2. Abdominal breathing
3. Thoracic breathing
4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Question 30. Tidal volume is

1. The volume of air breathed in or out in one normal inspiration/expiration
2. The volume of air breathed out by forced expiration alters normal inspiration
3. The volume of air breathed out by forced expiration after forced inspiration
4. The volume of air that remains in the lungs even after maximum expiration

Answer: 1. The volume of air breathed in or out in one normal inspiration/expiration

Question 31. Which of the following pulmonary volumes cannot be measured by spirometer directly?

1. Nodal volume
2. Vital capacity
3. Inspiratory capacity
4. Residual volume

Answer: 4. Residual volume

Question 32. Ribs move outward during respiration with

1. Intercostal muscles
2. Petrohyal muscles
3. Pharyngeal muscles
4. None of these

Answer: 1. Intercostal muscles

Question 33. Functional residual capacity (FRC) includes

1. TV

2. IRV

3. RV

4. ERV

1. (1) + (3)
2. (2) + (4)
3. (3) + (4)
4. (1) + (2) + (4)

Answer: 3. (3) + (4)

Question 34. If a person exhales forcefully by applying all his efforts, what will be the pulmonary volume inhaled by him immediately under normal conditions without applying any extra effort?

1. TV + IRV
2. TV only
3. TV + ERV
4. TV + IRV + ERV

Answer: 3. TV + ERV

Question 35. The pco₂ level in the expired air under normal conditions is approximately

1. 46 mm of Hg
2. 100 mm of Hg
3. 32 mm of Hg
4. 116 mm of Hg

Answer: 3. 32 mm of Hg

Question 36. Which of the following factors will decrease oxygenation?

1. High Hb
2. Increased blood flow
3. Anemia
4. Increased blood volume

Answer: 3. Anemia

Question 37. Which statement is wrong?

1. The partial pressure of CO₂ (pco₂) is higher in the air inside the lungs than inside the venous blood.
2. The partial pressure of O₂ (po₂) is higher in the air inside the lungs than in the arterial blood.
3. The partial pressure of CO₂ (po₂,) is lower inside the venous blood than in the air in the lung.
4. The partial pressure of CO₂ (pco₂) is higher inside the venous blood than in the air.

Answer: 1. The partial pressure of CO₂ (pco₂) is higher in the air inside the lungs than inside the venous blood.

Question 38. The exchange of gases between alveolar air and alveolar capillaries occurs by

1. Osmosis
2. Active transport
3. Absorption
4. Diffusion

Answer: 4. Diffusion

Question 39. The amount of oxygen transported by 1L of blood under strenuous conditions is approximately

1. 5 mL
2. 50 mL
3. 15 mL
4. 150 mL

Answer: 4. 150 mL

Question 40. In alveoli, surfactant is produced by

1. Type 1 pneumocyte
2. Type 2 pneumocyte
3. Kupflcr’s cells
4. Dust cells

Answer: 2. Type 2 pneumocyte

Question 41. The combination of O₂ with hemoglobin can be increased mostly by

1. Increasing O₂ concentration in air
2. Decreasing O₂ concentration in blood
3. Increasing CO₂ concentration in air
4. Decreasing CO₂ concentration in blood

Answer: 4. Decreasing CO₂ concentration in blood

Question 42. The effect of CO₂ concentration on the dissociation of oxyhemoglobin was explained by

1. G.S. Carter
2. Yapp
3. William Hoar
4. Christian Bohr

Answer: 4. Christian Bohr

Question 43. The oxygen hemoglobin dissociation curve will shift to the right on the decrease of

1. Acidity
2. Carbon dioxide concentration
3. Temperature
4. PH

Answer: 4. PH

Question 44. If CO₂ level gels increase in the blood, it favors

1. Loading of O₂ in the blood
2. Unloading of O₂ from the blood
3. Decreased availability of oxygen to tissues
4. Both (1) and (3)

Answer: 2. Unloading of O₂ from the blood

Question 45.If oxyhemoglobin dissociation curves are drawn for maternal and fetal hemoglobin, which of the following is true?

1. The maternal curve will be on the right side
2. The fetal curve will be on the right side
3. Both will overlap each other
4. It will depend upon the Pco₂ level

Answer: 1. Maternal curve will be on the right side

Question 46. The reverse of the chloride shift occurs during

1. Internal respiration
2. External respiration
3. Cellular respiration
4. Anaerobic respiration

Answer: 2. External respiration

Question 47. The percentage amount of CO₂ carried or transported by Hb is

1. 10%
2. 80%
3. 70%
4. 23%

Answer: 4. 23%

Question 48.In the process of transport of CO₂, which phenomenon occurs between RBCs and plasma?

1. Osmosis
2. Adsorption
3. Chloride shift
4. Absorption

Answer: 3. Chloride shift

Question 49. Which of the following can be termed as the opposite of Bohr’s effect?

1. Haldane’s effect
2. Hamburger’s phenomenon
3. Hering-Breuer reflex
4. None of these

Answer: 1. Haldane’s effect

Question 50. The impulse for voluntary muscles for forced breathing starts in

1. Cerebellum
2. Medulla
3. Vagus nerve
4. Cerebrum

Answer: 4. Cerebrum

Question 51. The respiratory control center lies in

1. Pons
2. Medulla oblongata
3. Cerebrum
4. Both (1) and (2)

Answer: 4. Both (1) and (2)

Question 52. Which of the following statements is wrong?

1. The inspiratory center increases the strength of the contraction of rib muscles.
2. The pneumatic center controls the switch-off point of inspiration.
3. Breathing movements are caused by changes in the concentration of CO₂ in the blood.
4. The expiratory center lies in pons and inspiratory center lies in medulla.

Answer: 4. The expiratory center lies in the pons and the inspiratory center lies in the medulla.

Question 53. Which of the following controls the switch-off point of inspiration?

1. Apneustic center
2. Pneumotaxic center
3. Pons varolii
4. Cerebrum

Answer: 2. Pneumotaxic center

Question 54. Which of the following is not possible when the pneumatic center is sending a strong signal?

1. The rate of breathing increases
2. Complete filling of lungs
3. Decreased duration of inspiration
4. Decreased duration of expiration

Answer: 2. Complete filling of lungs

Question 55. Overstretching of the lungs is prevented due to

1. Bohr’s effect
2. Hering-Breuer reflex
3. Conditioned reflex
4. Haldane’s effect

Answer: 2. Hering-Breuer reflex

Question 56. The rate and depth of respiration shall increase when

1. Oxygen concentration increases
2. CO₂ concentration increases in alveolar air
3. Bicarbonate concentration increases
4. Bicarbonate concentration decreases

Answer: 2. CO₂ concentration increases in alveolar air

Question 57. The “mountain sickness” in persons climbing to high altitudes without any aid of oxygen cylinders is due to

1. Anemic hypoxia
2. Arterial hypoxia
3. Lack of sufficient amount of hemoglobin
4. Lack of a sufficient number of erythrocytes

Answer: 2. Arterial hypoxia

Question 58. Cyanide poisoning will lead to

1. Hypoxic hypoxia
2. Histotoxic hypoxia
3. Stagnant hypoxia
4. Anemic hypoxia

Answer: 2. Histotoxic hypoxia

Question 59. Asthma is caused to

1. Infection of trachea
2. Infection of lungs
3. Bleeding into the pleural cavity
4. Spasm in bronchial muscles

Answer: 4. Spasm in bronchial muscles

Question 60. Which of the following is related to occupational lung disease?

1. Silicosis
2. Asbestosis
3. Fibrosis of the upper part of the lung
4. All of these

Answer: 4. All of these

Question 61. The breakdown of the alveoli of the lungs resulting in the reduced surface area for gas exchange is known as

1. Emphysema
2. Sneezing
3. Pneumonia
4. Tuberculosis

Answer: 1. Emphysema

Question 62. If the thorax is injured and the pleura is damaged, the air enters the pleural cavity and the lungs are collapsed. This condition is known as

1. Hyponea
2. Orthopnea
3. Dyspnea
4. Pneumothorax

Answer: 4. Pneumothorax

Question 63. Protective respiratory blast is

1. Hiccupping
2. Coughing
3. Sneezing
4. None of these

Answer: 3. Sneezing

Question 64. Low oxygen tension in the blood causes

1. Coughing
2. Hiccups
3. Sneezing
4. Yawning

Answer: 4. Yawning

Question 65.Disorder/disease related to the bubbling of N₂ in the blood resulting in pain or severe problems is

1. Caisson’s disease
2. Cheyne-stokes respiration
3. Hypopnea
4. Asthma

Answer: 1. Caisson’s disease

Question 66. With the increase in temperature, the respiratory rate will

1. Increase
2. Decrease rapidly
3. Remain unaffected
4. Decrease slowly

Answer: 1. Increase

Question 67. Which of the following gases makes the most stable combination with the hemoglobin of red blood cells?

1. CO₂
2. CO
3. O₂
4. N₂

Answer: 2. CO

Question 68. One of the following is not a respiratory pigment.

1. Hemoglobin
2. Chlorocruorin
3. Hemocyanin
4. Hemozoin

Answer: 4. Hemozoin

Question 69. Pneumonia can be caused by

1. Bacteria (Streptococcus pneumoniae)
2. Protozoan
3. Fungi
4. All of these

Answer: 4. All of these

Question 70. Asbestosis or silicosis is characterized by the proliferation of fibrous tissue in

1. Respiratory tract
2. The upper part of the lung
3. The lower part of the lung
4. Pulmonary capillary

Answer: 2. Upper part of a lung

Question 71. The respiratory system is derived from

1. Endoderm
2. Mesoderm
3. Ectoderm
4. None of these

Answer: 1. Endoderm

Question 72. Which of the following is false?

1. Blood from the right side of the heart is carried to the lungs by the pulmonary artery.
2. Pleura is double covering of the kidney.
3. The pancreas is both an exocrine and endocrine gland.
4. Scurvy is due to vitamin C deficiency.

Answer: 2. Pleura is a double covering of the kidney.

Question 73. Pericardial fluid is secreted by

1. Myocardium
2. Parietal peritoneum
3. Visceral peritoneum
4. None of these

Answer: 3. Visceral peritoneum

Question 74. Vocal cords occur in

1. Larynx
2. Pharynx
3. Glottis
4. Bronchial tube

Answer: 1. Larynx

Question 75.Body tissues obtain oxygen from hemoglobin because of its dissociation in tissues caused by

1. Low oxygen concentration and high carbon dioxide concentration
2. Low oxygen concentration
3. Low carbon dioxide concentration
4. High carbon dioxide concentration

Answer: 4. High carbon dioxide concentration

Question 76. Lungs have a large number of alveoli for

1. Having a spongy texture and proper shape
2. More surface area for diffusion of gases
3. More space for increasing the volume of inspired air
4. More nerve supply

Answer: 2. More surface area for diffusion of gases

Question 77. Respiratory organs in scorpion are

1. Gills
2. Book lungs
3. Skin
4. Book gills

Answer: 2. Book lungs

Question 78. Which energy is consumed in breathing?

1. Mechanical
2. Chemical
3. Bioelectrical
4. Physical

Answer: 2. Chemical

Question 79. During inspiration, the diaphragm

1. Relaxes
2. Contracts
3. Expands
4. Shows no change

Answer: 2. Contracts

Question 80. In which form CO₂ is carried in blood?

1. Sodium bicarbonate
2. Sodium carbonate
3. Potassium carbonate
4. Magnesium carbonate

Answer: 1. Sodium bicarbonate

Question 81. The vital capacity of the human lung is equal to

1. 3500 mL
2. 4800 mL
3. 500 mL
4. 1200 mL

Answer: 2. 4800 mL

Question 82. The type of respiration in mammals is called

1. Pulmonary respiration
2. Gill respiration
3. Cutaneous respiration
4. Tracheal respiration

Answer: 1. Pulmonary respiration

Question 83. Normal breathing is called

1. Apnea
2. Dyspnea
3. Eupnea
4. Hyperpnca

Answer: 3. Eupnea

Question 84. Mb most strongly combines with

1. CO
2. O₂
3. CO₂
4. O₃

Answer: 1. CO

Question 85. Tissue respiration is a process by which

1. Carbohydrates are synthesized
2. Proteins are broken down
3. Fat molecules are metabolized
4. Energy is liberated

Answer: 4. Energy is liberated

Question 86. The exchange of gases in lung alveoli occurs through

1. Active transport
2. Osmosis
3. Simple diffusion
4. Passive transport

Answer: 3. Simple diffusion

Question 87. CO₂ is mainly transported by

1. Respiratory pigment
2. Dissolution of gases
3. O₂ taken by tissues
4. Bicarbonates

Answer: 2. Dissolution of gases

Question 88. In which form iron is present in hemoglobin?

1. Ionic
2. Unionic
3. Fe²⁺
4. Fe³⁺

Answer: 3. Fe²⁺

Question 89. Ventilation/respiratory control is present in

1. Medulla oblongata
2. Cerebellum
3. Cerebrum
4. Diencephalon

Answer: 1. Medulla oblongata

Question 90. Match the columns

1. (1) → (C), (2) → (D), (3) → 4 (B), (4) → (A)
2. (1) → 4 (E), (2) → 4 (D), (3) → 4 (A), (4) → 4 (B)
3. (1) → 4 (D), (2) → 4 (D), (3) → 4 (B), (4) → 4 (E)
4. (1) → 4 (D), (2) → 4 (E), (3) → 4 (B), (4) → 4 (A)

Answer: 1. (1) → (C), (2) → (D), (3) → 4 (B), (4) → (A)

Question 91. The respiratory center is present in

1. Cerebrum
2. Hypothalamus
3. Cerebellum
4. Medulla oblongata

Answer: 4. Medulla oblongata

Question 92. Which of the following is shifted in chloride shift?

1. O₂ and CO₂
2. Bicarbonate ions
3. CO₂
4. O₂

Answer: 2. Bicarbonate ions

Question 93. Which one of the following is capable of carrying oxygen?

1. Plasma
2. Blood
3. Serum
4. Lymph

Answer: 2. Blood

Question 94. Bicarbonate ions can be generated in

1. Lymphocytes
2. Neutrophil
3. Basophil
4. RBCs

Answer: 4. RBCs

Question 95. Adam’s apple represents

1. Cricoid cartilage
2. Thyroid cartilage
3. Both (1) and (2)
4. None of the above

Answer: 2. Thyroid cartilage

Question 96. The amount of oxygen which is present in 1g of Hb is

1. 1.34 mL
2. 13.4 mL
3. 134 mL
4. 20 mL

Answer: 1. 1.34 mL

Question 97. Book lungs are respiratory organs of

1. Mollusca
2. Mammals
3. Arachnida
4. Earthworm

Answer: 3. Arachnida

Question 98. The respiratory center in the brain is stimulated by

1. CO₂ concentration in venous blood
2. O₂ concentration in arterial blood
3. CO₂ concentration in artery blood
4. O₂ concentration in venous blood

Answer: 3. CO₂ concentration in artery blood

Question 99. The energy currency of a cell is

1. 10 AMP
2. ATP
3. Carbohydrates
4. NAD

Answer: 2. ATP

Question 100. What can determine the percentage of oxygen earned by Hb?

1. PH of blood
2. Percentage of CO₂
3. Partial pressure of oxygen
4. All of above

Answer: 4. All of the above

Question 101. Hamburger’s effect is also known as

1. Sodium shift
2. Chloride shift
3. Lead shift
4. None of these

Answer: 2. Chloride shift

Question 102. The correct order of structures through which the ait- passes in the body is

1. Nasal cavity, larynx, trachea, bronchi air sacs
2. Bronchi, nasal cavity, larynx, trachea air sacs
3. Larynx bronchi, nasal cavity, trachea air sacs
4. Nasal cavity, trachea, larynx, bronchi air sacs

Answer: 1. Nasal cavity, larynx, trachea, bronchi air sacs

Question 103. During inspiration,

1. The diaphragm gets raised and the ribs get lowered
2. Both the diaphragm and ribs get lowered
3. Ribs get raised and the diaphragm gets lowered
4. The diaphragm gets flattered and ribs get raised

Answer: 4. The diaphragm gets flattered and ribs get raised

Question 104. Which one of the following can respire in the absence of oxygen?

1. Amoeba
2. Tapeworm
3. House fly
4. Hydra

Answer: 2. Tapeworm

Question 105.When CO₂ concentration in the blood increases, breathing becomes

1. Slow and deep
2. Faster and deeper
3. Shallower and slow
4. There is no effect on breathing

Answer: 2. Faster and deeper

Question 106. The ascent of high mountains may cause altitude sickness in men. The prime cause of this is

1. Excess of CO₂ in blood
2. Decreased efficiency of hemoglobin
3. Decreased partial pressure of oxygen
4. Decreased proportion of oxygen in the air

Answer: 3. Decreased partial pressure of oxygen

Question 107. In the lungs, there is a definite exchange of ions between RBC and plasma. Removal of CO₂ from blood involves

1. Efflux of Cl^– ions from RBC
2. An influx of Cl^– ions into RBC
3. An influx of HCO₃^– ions into RBC
4. Efflux of HCO₃^– ions from RBC

Answer: 1. Efflux of Cl ions from RBC

Question 108. Which enzyme is most abundantly found in RBC?

1. Carbonic anhydrase
2. Hemoglobin
3. Albumin
4. Thrombinasc

Answer: 1. Carbonic anhydrase

Question 109. The combination of O₂ with hemoglobin can be increased mostly by

1. Decreasing O₂ concentration in blood
2. Increasing O₂ concentration in the air
3. Increasing CO₂ concentration in air
4. Decreasing CO₂ concentration in air

Answer: 2. Increasing O₂ concentration in the air

Question 110. SARS is caused by the variant of

1. Pneumococcus pneumonia
2. Common cold coronavirus
3. Asthma
4. Bronchitis

Answer: 2. Common cold coronavirus

Question 111. Pleurisy is the disease of

1. Liver
2. Heart
3. Lungs
4. Kidneys

Answer: 3. Lungs

Question 112. At higher altitudes, a man suffers much from

1. Cold
2. Oxygen deficiency
3. Higher atmospheric pressure
4. Ultraviolet radiations

Answer: 2. Oxygen deficiency

Question 113. Tuberculosis in men is caused by

1. Tuberculosis virus
2. Streptococci
3. Staphylococci
4. Tuberculosis bacillus

Answer: 4. Tuberculosis bacillus

Question 114. Asthma is a respiration disease caused due to

1. Infection of lungs
2. Tracheal infection
3. Bleeding in the pleural cavity
4. Cramps in the bronchial muscles obstructing the air passage

Answer: 4. Cramps in the bronchial muscles obstructing the air passage

Question 115. The exchange of gases in lung alveoli occurs through

1. Active transport
2. Osmosis
3. Simple diffusion
4. Passive transport

Answer: 3. Simple diffusion

Question 116. Vocal cords occur in

1. Pharynx
2. Larynx
3. Glottis
4. Bronchial tube

Answer: 2. Larynx

Question 117. Adam’s apple represents

1. Arytenoid cartilage of larynx
2. Cricoid cartilage of larynx
3. Thyroid cartilage of larynx
4. All the above

Answer: 4. All the above

Question 118. The respiratory center of the brain is stimulated by

1. Carbon dioxide content in venous blood
2. Carbon dioxide content in arterial blood
3. Oxygen content in venous blood
4. Oxygen content in arterial blood

Answer: 2. Carbon dioxide content in arterial blood

Question 119. Carbon dioxide entering erythrocytes reacts with water to form carbonic acid. The enzyme is

1. Carbonic anhydrase
2. Carboxypeptidase
3. Hydrolase
4. Oxidoreductase

Answer: 1. Carbonic anhydrase

Question 120. Arytenoid cartilage is found in

1. Hyoid
2. Sternum
3. Larynx
4. Nose

Answer: 3. Larynx

Question 121. At the time of expiration, the diaphragm becomes

1. Oblique
2. Normal
3. Flattened
4. Dome-shaped

Answer: 4. Dome-shaped

Question 122. The exchange of bicarbonates and chloride ions between RBC and plasma is called

1. Chloride shift
2. Bohr’s effect
3. Haldane’s effect
4. Intracellular respiration

Answer: 1. Chloride shift

Question 123.When CO₂ concentration in the blood increases, breathing becomes

1. There is no effect on breathing
2. Slow and deep
3. Faster
4. Shallower and slow

Answer: 3. Faster

Question 124. If CO₂ concentration increases in the blood, then breathing will

1. Increases
2. Decrease
3. Stop
4. Remain unchanged

Answer: 1. Increases

Question 125. Hering-Breuer reflex is related to the

1. Effect of pH on respiratory center
2. Effect of CO₂ on Respiratory Center
3. Effect of nerves on respiratory center
4. Effect of temperature on respiratory center

Answer: 3. Effect of nerves on respiratory center

Question 126. The toxic effect of carbon monoxide is due to its greater affinity for hemoglobin as compared to oxygen

1. 2 times
2. 20 times
3. 200 times
4. 300 times

Answer: 4. 200 times

Question 127. CO₂ is transported mainly by

1. Plasma
2. Carbonic acid
3. Bicarbonate
4. Carboxyhemoglobin

Answer: 3. Bicarbonate

Question 128. By which mechanism, is oxygen r, transported from the lung to cells

1. Diffusion
2. Facilitated diffusion
3. Transpiration
4. Osmosis

Answer: 1. Diffusion

Question 129. Why is CO poisonous for man?

1. CO affects the nerves of the lungs.
2. CO affects the diaphragm and intercostal muscles.
3. CO reacts with oxygen reducing a percentage of O₂ in air.
4. Hemoglobin combines with CO instead of O₂ and the product cannot dissociate,

Answer: 4. Hemoglobin combines with CO instead of O₂ and the product cannot dissociate,

Question 130. One hemoglobin carries how many molecules of O₂?

1. 4
2. 2
3. 6
4. 8

Answer: 1. 4

Question 131. The respiratory center is present in

1. Cerebellum
2. Cerebrum
3. Medulla oblongata
4. Hypothalamus

Answer: 3. Medulla oblongata

Question 132. After deep inspiration, the capacity of maximum expiration of the lung is called

1. Total lung capacity
2. Functional residual capacity
3. Vital capacity
4. Inspiratory capacity

Answer: 3. Vital capacity

Question 133. Pneumotaxic center is present in

1. Cerebrum
2. Cerebellum
3. Medulla oblongata
4. Pons Varolii

Answer: 4. Pons Varolii

Question 134. Hamburger’s shift is also known as

1. Bicarbonate shift
2. Chloride shift
3. Potassium shift
4. All of these

Answer: 2. Chloride shift

Question 135. Hemoglobin shows maximum affinity with

1. Carbon monoxide
2. Carbon dioxide
3. Oxygen
4. Ammonia

Answer: 1. Carbon monoxide

Question 136. The dissociation curve shifts to the right when

1. CO₂ concentration decreases
2. CO₂ concentration increases
3. O₂ concentration decrease
4. Cl concentration increases

Answer: 2. CO₂ concentration increases

Question 137. The epithelium of bronchioles is

1. Pseudostratified and columnar
2. Squamous and sensory
3. Pseudostratified and sensory
4. Cuboidal and columnar

Answer: 2. Squamous and sensory

Question 138. If a man from the coast goes to Everest Peak, then

1. His breathing and heartbeat will increase
2. His breathing and heartbeat will decrease
3. His respiratory rate will decrease
4. His heartbeat will decrease

Answer: 1. His breathing and heartbeat will increase

Question 139. The structure which prevents the entry of food into the windpipe is

1. Gullet
2. Glottis
3. Tonsil
4. Epiglottis

Answer: 4. Epiglottis

Question 140. In which of the following animals, respiration occurs without a respiratory organ?

1. Fish
2. Cockroach
3. Tadpole
4. Earthworm

Answer: 4. Earthworm

Question 141. Carbonic anhydrase is found in high concentrations in

1. Leucocytes
2. Blood plasma
3. Erythrocytes
4. Lymphocytes

Answer: 3. Erythrocytes

Question 142. What would happen if human blood becomes acidic (low pH)?

1. The oxygen-carrying capacity of hemoglobin increases.
2. The oxygen-carrying capacity of hemoglobin decreases.
3. RBC count increases.
4. RBC count decreases.

Answer: 2. Oxygen-carrying capacity of hemoglobin decreases.

Question 143. Dissociation of oxyhemoglobin can be promoted by

1. Low blood pH
2. High body temperature
3. Low body temperature
4. High blood pH

Answer: 2. High body temperature

Question 144. Which of the following is correct regarding respiration?

1. No organism can live without respiration.
2. It takes place at every time day and night.
3. It involves the production of carbon dioxide and water.
4. All of these.

Answer: 4. All of these

Question 145. Respiratory coefficient is

1. The amount of CO₂ produced to O₂ absorbed.
2. The amount of O₂ obtained to the amount of O₂ consumed.
3. Always more than one.
4. Always less than one.

Answer: 1. The amount of CO₂ produced to O₂ absorbed.

Question 146. Dyspnea is the

1. Normal breathing
2. Difficult breathing
3. Rapid breathing
4. Stage without breathing

Answer: 2. Difficult breathing

Question 147. Oxygen carrier or respiratory pigment in the blood of frogs and other vertebrates is

1. Hemocyanin
2. Cytochrome
3. Hemoglobin
4. None of these

Answer: 3. None of these

Question 148. During the transport of CO₂, blood does not become acidic due to

1. Neutralization of H₂CO₃ by Na₂CO₃
2. Absorption by leucocytes
3. Blood buffers
4. Non-accumulation

Answer: 3. Blood buffers

Question 149. The respiratory center, which regulates respiration, is located in

1. Cerebral peduncle
2. Vagus nerve
3. Pons
4. Medulla oblongata

Answer: 4. Medulla oblongata

Question 150. The respiratory mechanism is controlled by

1. Central nervous system
2. Sympathetic nervous system
3. Parasympathetic nervous system
4. Autonomic nervous system

Answer: 1. Central nervous system

Question 151. Low oxygen tension in the blood causes

1. Coughing
2. Yawning
3. Hiccupping
4. Sneezing

Answer: 2. Yawning

Question 152. The oxyhemoglobin dissociation curve is

1. Sigmoid
2. Hyperbolic
3. Straight line
4. Parabolic

Answer: 1. Sigmoid

Question 153. The affinity of CO with Hb is more than oxygen by

1. 2 times
2. 20 times
3. 200 times
4. 2000 times

Answer: 3. 200 times

Question 154. The exchange of gases in the lungs is by

1. Simple diffusion
2. Active transport
3. Passive transport
4. Osmosis

Answer: 1. Simple diffusion

Question 155. The covering of the lungs is called

1. Pleura
2. Pericardia
3. Peritoneum
4. Mediastinum

Answer: 1. Pleura

Question 156. The hamburger phenomenon is also known as

1. Calcium shift
2. Bohr effect
3. Chloride shift
4. Na⁺-K⁺ pump

Answer: 3. Chloride shift

Question 157. Even when there is no air in it, the human trachea does not collapse due to the presence of %

1. Bony rings
2. Turgid pressure
3. Chitinous rings
4. Cartilaginous rings

Answer: 4. Cartilaginous rings

Question 158. The specialty common in the alveoli of the lungs and villi of the intestine in mammals is that both

1. Provide a large surface area
2. Have ciliated epithelium
3. Are suited for diffusion of gases
4. Have a rich supply of blood vessels and lymph ducts

Answer: 1. Provide a large surface area

Question 159. The movement of true vocal cords in man is controlled by cartilage

1. Arytenoids
2. Cricoid
3. Thyroid
4. Both (1) and (2)

Answer: 1. Arytenoids

Question 160. The presence of a large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is

1. Inefficient system of ventilation with little residual air
2. Inefficient system of ventilation with a high percentage of residual air
3. Efficient system of ventilation with no residual air
4. Efficient system of ventilation with little residual air

Answer: 4. Efficient system of ventilation with little residual air

Question 161. The sites of gaseous exchange in the lungs are

1. Tracheoles
2. Alveoli
3. Bronchioles
4. Pulmonary chambers

Answer: 2. Alveoli

Question 162. Exposure to carbon monoxide (from coal gas) is extremely dangerous and can kill a patient because

1. The compound carboxy-hemoglobin is formed with hemoglobin which can gradually clot the blood resulting in circulatory failure.
2. Carboxyhemoglobin reduces the ability of blood to transport oxygen by rupturing a vast majority of erythrocytes.
3. Carboxyhemoglobin greatly modifies the structure of hemoglobin, thus making it lose its affinity for oxygen.
4. The compound formed, carboxy-hemoglobin does not allow RBCs to act for their respiratory function.

Answer: 2. Carboxyhemoglobin reduces the ability of blood to transport oxygen by rupturing a vast majority of erythrocytes.

Question 163. During inspiration, the diaphragm

1. Relaxes to become dome-shaped
2. Contracts and flattens
3. Expands
4. Shows no change

Answer: 2. Contracts and flattens

Question 164. Which is correct?

1. Respiratory centers are not affected by CO₂
2. In humans, vital capacity is just double the expiratory volume.
3. A human lung has 1000 alveoli.
4. During inspiration, the lungs act as a suction pump.

Answer: 4. During inspiration, the lungs act as a suction pump.

Question 165. In the lungs, the air is separated from the venous blood through

1. Squamous epithelium + Endothelium of blood vessel
2. Squamous epithelium + Tunica externa, media, and internet of blood
3. Squamous epithelium + Basement membrane + Endothelium of blood vessels
4. None of these

Answer: 3. Squamous epithelium + Basement membrane + Endothelium of blood vessels

Question 166. Intercostal muscle arc found attached with

1. Diaphragm
2. Ribs
3. Pleura
4. Lungs

Answer: 2. Ribs

Question 167. Match the disorders given in column I with symptoms under column II. Choose the answer which gives the correct combination of alphabets with numbers.

1. A = 4, B=2, C = 5, D = 1
2. A= 5, B = 3, C = 2, D = 1
3. A= 3, B = 1, C = 5, D = 4
4. A = 2, B = 4, C = 1, D = 3

Answer: 4. A = 2, B = 4, C = 1, D = 3

Question 168. In the lungs, there is a definite exchange of ions between RBC and plasma. Removal of CO₂ from blood involves

1. The influx of Cl^– ions into RBC
2. The influx of HCO₃^– tons into RBC
3. Efflux of Cl ions from RBC
4. Efflux of HCO₃^– ions from RBC

Answer: 4. Efflux of HCO₃^– ions from RBC

Question 169. Which one of the following statements is incorrect?

1. The presence of non-respiratory air sacs increases the efficiency of respiration in birds.
2. In insects, circulating body fluids serve to distribute oxygen to tissues.
3. The principle of countercurrent flow facilitates efficient respiration in the gills of fish.
4. The residual air in the lungs slightly decreases the efficiency of respiration in mammals.

Answer: 2. In insects, circulating body fluids serve to distribute oxygen to tissues.

Question 170. Consider the following statements:

1. Carbonic anhydrase is present in the erythrocytes

2. In erythrocytes, carbon dioxide combines with water and is transported.

1. Statement A is correct and is responsible for Statement B.
2. Statement A is not correct, but statement B is correct.
3. Both statements A and B are wrong,
4. Statement A is correct, but not involved in statement

Answer: 1. Statement A is correct and is responsible for Statement B.

Question 171. Carboxyhemoglobin complex results due to this pollutant?

1. CO₂
2. CO
3. H₂CO₃
4. SO₂

Answer: 2. CO₂

Question 172. Listed below are four respiratory capacities (a-d) and four jumbled respiratory volumes of a normal human adult. Respiratory capacities Respiratory volumes

Which one of the following is the correct matching of capacities and volumes?

1. 4500 mL, B.3500mL
2. 2500 mL, C. 4500mL
3. 1200 mL, D.2500mL
4. 3500 mL, A. 1200mL

Answer: 4. 3500 mL, A. 1200mL

Question 173. What is true about RBCs in humans?

1. They do not cany CO₂ at all.
2. They cany about 20-25% of CO-,
3. They transport 99.5% of O₂.
4. They transport about 80% oxygen only and the rest 20% of it is transported in a dissolved state in blood plasma.

Answer: 2. They cany about 20-25% of CO-,

Question 174. Which one of the following is the correct statement for respiration in humans?

1. Neural signals from the pneumotoxic center in the pons region of the brain can increase the duration of inspiration.
2. Workers in grinding and stone-breaking industries may suffer from lung fibrosis.
3. About 90% of carbon dioxide (CO₂) is carried by hemoglobin as carbamino-hemoglobin.
4. Cigarette smoking may lead to inflammation of the bronchi.

Answer: 2. Workers in grinding and stone-breaking industries may suffer from lung fibrosis.

Question 175. The human respiratory system with labels A, B, C, and D. Select the option that gives correct identification and main function and/or characteristic.

1. B—Pleural membrane—Surrounds ribs on both sides to provide cushion against rubbing.
2. C—Alveoli—Thin-walled vascular bag-like structures for the exchange of gases.
3. D—The lower end of the lungs—Diaphragm pulls it down during inspiration.
4. A—Trachea—Long tube supported by complete cartilaginous rings for conducting inspired air

Answer: 2. C—Alveoli—Thin-walled vascular bag-like structures for the exchange of gases.