NEET Biology Breathing and Exchange of Gases MCQs Set 18

Answer: (a) epiglottis

Explanation:
1. During swallowing the epiglottis, a cartilaginous flap, covers the glottis so that food passes into the oesophagus.

Teacher's Note:
1. T
2. h
3. e
4.
5. e
6. p
7. i
8. g
9. l
10. o
11. t
12. t
13. i
14. s
15.
16. c
17. l
18. o
19. s
20. e
21. s
22.
23. t
24. h
25. e
26.
27. o
28. p
29. e
30. n
31. i
32. n
33. g
34.
35. o
36. f
37.
38. t
39. h
40. e
41.
42. l
43. a
44. r
45. y
46. n
47. x
48.
49. w
50. h
51. i
52. l
53. e
54.
55. s
56. w
57. a
58. l
59. l
60. o
61. w
62. i
63. n
64. g
65. .

Answer: (a) erythrocytes

Explanation:
1. Carbonic anhydrase in red blood cells speeds up the reaction \( CO_2 + H_2O \rightleftharpoons H_2CO_3 \).

Teacher's Note:
1. T
2. h
3. i
4. s
5.
6. e
7. n
8. z
9. y
10. m
11. e
12.
13. i
14. s
15.
16. t
17. h
18. e
19.
20. k
21. e
22. y
23.
24. t
25. o
26.
27. C
28. O
29. \
30. (
31.
32. _
33. 2
34.
35. \
36. )
37.
38. t
39. r
40. a
41. n
42. s
43. p
44. o
45. r
46. t
47.
48. a
49. s
50.
51. b
52. i
53. c
54. a
55. r
56. b
57. o
58. n
59. a
60. t
61. e
62. .

Answer: (a) 5800 mL

Explanation:
1. Total lung capacity is vital capacity plus residual volume, about 4600 plus 1200, i.e. roughly 5800 mL.

Teacher's Note:
1. T
2. o
3. t
4. a
5. l
6.
7. l
8. u
9. n
10. g
11.
12. c
13. a
14. p
15. a
16. c
17. i
18. t
19. y
20.
21. i
22. s
23.
24. t
25. h
26. e
27.
28. v
29. o
30. l
31. u
32. m
33. e
34.
35. o
36. f
37.
38. a
39. i
40. r
41.
42. i
43. n
44.
45. t
46. h
47. e
48.
49. l
50. u
51. n
52. g
53. s
54.
55. a
56. f
57. t
58. e
59. r
60.
61. a
62.
63. m
64. a
65. x
66. i
67. m
68. u
69. m
70.
71. i
72. n
73. s
74. p
75. i
76. r
77. a
78. t
79. i
80. o
81. n
82. .

Answer: (a) spirometer

Explanation:
1. A spirometer records the volume of air inspired or expired, from which lung volumes and capacities are calculated.

Teacher's Note:
1. S
2. p
3. i
4. r
5. o
6. m
7. e
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9. r
10. y
11.
12. i
13. s
14.
15. u
16. s
17. e
18. d
19.
20. t
21. o
22.
23. a
24. s
25. s
26. e
27. s
28. s
29.
30. l
31. u
32. n
33. g
34.
35. f
36. u
37. n
38. c
39. t
40. i
41. o
42. n
43. .

Answer: (a) alveoli

Explanation:
1. Residual volume is the air that stays in the lungs after a forced expiration. It remains mainly in the alveoli.

Teacher's Note:
1. I
2. t
3.
4. k
5. e
6. e
7. p
8. s
9.
10. t
11. h
12. e
13.
14. a
15. l
16. v
17. e
18. o
19. l
20. i
21.
22. f
23. r
24. o
25. m
26.
27. c
28. o
29. l
30. l
31. a
32. p
33. s
34. i
35. n
36. g
37. .

Answer: (a) medulla oblongata

Explanation:
1. The rhythm centre is in the medulla oblongata, with the pneumotaxic centre in the pons.

Teacher's Note:
1. T
2. h
3. e
4.
5. m
6. e
7. d
8. u
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10. l
11. a
12.
13. s
14. e
15. t
16. s
17.
18. t
19. h
20. e
21.
22. b
23. a
24. s
25. i
26. c
27.
28. r
29. h
30. y
31. t
32. h
33. m
34.
35. o
36. f
37.
38. b
39. r
40. e
41. a
42. t
43. h
44. i
45. n
46. g
47. .

Answer: (a) 4

Explanation:
1. Haemoglobin has four haem groups, each of which binds one oxygen molecule.

Teacher's Note:
1. O
2. n
3. e
4.
5. H
6. b
7.
8. m
9. o
10. l
11. e
12. c
13. u
14. l
15. e
16.
17. c
18. a
19. n
20.
21. c
22. a
23. r
24. r
25. y
26.
27. f
28. o
29. u
30. r
31.
32. \
33. (
34.
35. O
36. _
37. 2
38.
39. \
40. )
41.
42. m
43. o
44. l
45. e
46. c
47. u
48. l
49. e
50. s
51. .

Answer: (a) Tracheal rings are made of hyaline cartilage

Explanation:
1. The incomplete C-shaped rings of the trachea are hyaline cartilage.
2. The dorsal side of the thorax is formed by the vertebral column.
3. Expiration occurs when the pressure in the lungs is positive.
4. High \( H^+ \) favours dissociation of oxyhaemoglobin.

Teacher's Note:
1. T
2. r
3. a
4. c
5. h
6. e
7. a
8. l
9.
10. r
11. i
12. n
13. g
14. s
15.
16. k
17. e
18. e
19. p
20.
21. t
22. h
23. e
24.
25. a
26. i
27. r
28. w
29. a
30. y
31.
32. o
33. p
34. e
35. n
36. .

Answer: (a) The volume of residual air is higher than the tidal volume

Explanation:
1. Residual volume is about 1100 to 1200 mL and tidal volume is about 500 mL.
2. Only about 20 to 25 percent of CO\( _2 \) is carried as carbaminohaemoglobin; about 70 percent is carried as bicarbonate.
3. Alveolar ventilation is less than pulmonary ventilation because of dead space.
4. Haemoglobin carries oxygen and carbonic anhydrase helps CO\( _2 \) transport.

Teacher's Note:
1. L
2. e
3. a
4. r
5. n
6.
7. t
8. h
9. e
10.
11. n
12. u
13. m
14. b
15. e
16. r
17. s
18. :
19.
20. T
21. V
22.
23. 5
24. 0
25. 0
26. ,
27.
28. R
29. V
30.
31. 1
32. 2
33. 0
34. 0
35. ,
36.
37. d
38. e
39. a
40. d
41.
42. s
43. p
44. a
45. c
46. e
47.
48. 1
49. 5
50. 0
51.
52. m
53. L
54. .

Answer: (a) The solubility of carbon dioxide is about 20 to 25 times higher than that of oxygen

Explanation:
1. Carbon dioxide is far more soluble in water than oxygen, so it diffuses across the membrane more easily.
2. Insects carry air directly to tissues through tracheae, not by blood.

Teacher's Note:
1. T
2. h
3. e
4.
5. h
6. i
7. g
8. h
9.
10. s
11. o
12. l
13. u
14. b
15. i
16. l
17. i
18. t
19. y
20.
21. o
22. f
23.
24. C
25. O
26. \
27. (
28.
29. _
30. 2
31.
32. \
33. )
34.
35. i
36. s
37.
38. w
39. h
40. y
41.
42. i
43. t
44. s
45.
46. d
47. i
48. f
49. f
50. u
51. s
52. i
53. o
54. n
55.
56. r
57. a
58. t
59. e
60.
61. i
62. s
63.
64. h
65. i
66. g
67. h
68. .

Answer: (b) blood buffers play an important role in \( CO_2 \) transport

Explanation:
1. Blood buffers, mainly the bicarbonate system and haemoglobin, take up the hydrogen ions formed.

Teacher's Note:
1. T
2. h
3. e
4.
5. b
6. i
7. c
8. a
9. r
10. b
11. o
12. n
13. a
14. t
15. e
16.
17. b
18. u
19. f
20. f
21. e
22. r
23.
24. s
25. y
26. s
27. t
28. e
29. m
30.
31. k
32. e
33. e
34. p
35. s
36.
37. b
38. l
39. o
40. o
41. d
42.
43. p
44. H
45.
46. n
47. e
48. a
49. r
50.
51. 7
52. .
53. 4
54. .

Answer: (a) plasma and erythrocytes

Explanation:
1. About 70 percent is carried as bicarbonate in plasma, and about 20 to 25 percent as carbaminohaemoglobin in RBCs, with a small part dissolved in plasma.

Teacher's Note:
1. B
2. o
3. t
4. h
5.
6. p
7. l
8. a
9. s
10. m
11. a
12.
13. a
14. n
15. d
16.
17. R
18. B
19. C
20. s
21.
22. t
23. a
24. k
25. e
26.
27. p
28. a
29. r
30. t
31.
32. i
33. n
34.
35. C
36. O
37. \
38. (
39.
40. _
41. 2
42.
43. \
44. )
45.
46. t
47. r
48. a
49. n
50. s
51. p
52. o
53. r
54. t
55. .

Answer: (d) all of the above

Explanation:
1. The nasal passages warm, moisten and filter the air before it reaches the lungs.

Teacher's Note:
1. H
2. a
3. i
4. r
5. s
6.
7. a
8. n
9. d
10.
11. m
12. u
13. c
14. u
15. s
16.
17. t
18. r
19. a
20. p
21.
22. d
23. u
24. s
25. t
26.
27. a
28. n
29. d
30.
31. m
32. i
33. c
34. r
35. o
36. b
37. e
38. s
39. .

Answer: (d) arched

Explanation:
1. During expiration the diaphragm relaxes and returns to its dome (arched) shape, which reduces the thoracic volume.

Teacher's Note:
1. C
2. o
3. n
4. t
5. r
6. a
7. c
8. t
9. i
10. o
11. n
12.
13. f
14. l
15. a
16. t
17. t
18. e
19. n
20. s
21.
22. t
23. h
24. e
25.
26. d
27. i
28. a
29. p
30. h
31. r
32. a
33. g
34. m
35.
36. i
37. n
38.
39. i
40. n
41. s
42. p
43. i
44. r
45. a
46. t
47. i
48. o
49. n
50. .

Answer: (b) 4800 mL

Explanation:
1. Vital capacity (about 3400 to 4800 mL) is the maximum volume that can be expired after a maximum inspiration.
2. Of the given options, 4800 mL matches.

Teacher's Note:
1. V
2. i
3. t
4. a
5. l
6.
7. c
8. a
9. p
10. a
11. c
12. i
13. t
14. y
15.
16. i
17. n
18. c
19. l
20. u
21. d
22. e
23. s
24.
25. I
26. R
27. V
28. ,
29.
30. T
31. V
32.
33. a
34. n
35. d
36.
37. E
38. R
39. V
40. .

Answer: (d) the diaphragm gets flattened and the ribs raised

Explanation:
1. The diaphragm contracts and flattens, and the external intercostal muscles lift the ribs and sternum.
2. The thoracic volume therefore increases.

Teacher's Note:
1. I
2. n
3. s
4. p
5. i
6. r
7. a
8. t
9. i
10. o
11. n
12.
13. i
14. s
15.
16. a
17. n
18.
19. a
20. c
21. t
22. i
23. v
24. e
25.
26. p
27. r
28. o
29. c
30. e
31. s
32. s
33. .

Answer: (b) more surface area for diffusion of gases

Explanation:
1. Millions of alveoli give a very large surface area, about 70 square metres, for gas exchange.

Teacher's Note:
1. L
2. a
3. r
4. g
5. e
6.
7. a
8. r
9. e
10. a
11.
12. a
13. n
14. d
15.
16. t
17. h
18. i
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20.
21. w
22. a
23. l
24. l
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26.
27. f
28. a
29. v
30. o
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32. r
33.
34. d
35. i
36. f
37. f
38. u
39. s
40. i
41. o
42. n
43. .

Answer: (d) tidal volume

Explanation:
1. Tidal volume is the air inspired or expired during normal quiet breathing, about 500 mL.

Teacher's Note:
1. T
2. i
3. d
4. a
5. l
6.
7. v
8. o
9. l
10. u
11. m
12. e
13.
14. i
15. s
16.
17. a
18. b
19. o
20. u
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22.
23. 6
24. 0
25. 0
26. 0
27.
28. t
29. o
30.
31. 8
32. 0
33. 0
34. 0
35.
36. m
37. L
38.
39. p
40. e
41. r
42.
43. m
44. i
45. n
46. u
47. t
48. e
49. .

Answer: (a) \( H_2O \) to form \( H^+ \) and \( HCO_3^- \); carbonic anhydrase

Explanation:
1. \( CO_2 + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^- \), catalysed by carbonic anhydrase.
2. The release of \( H^+ \) lowers the pH.

Teacher's Note:
1. C
2. a
3. r
4. b
5. o
6. n
7. i
8. c
9.
10. a
11. n
12. h
13. y
14. d
15. r
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20. s
21. p
22. e
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24. d
25. s
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31. h
32. e
33.
34. r
35. e
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37. c
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39. i
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42. .

Answer: (a) tidal volume

Explanation:
1. The volume moved in each normal breath is the tidal volume.

Teacher's Note:
1. I
2. t
3.
4. i
5. s
6.
7. a
8. b
9. o
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11. t
12.
13. 5
14. 0
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25.
26. a
27. d
28. u
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31. .