Class 11 Biology Chapter 14: Respiration in Plants – 100 MCQs with Answers
1. The main site of glycolysis is:
Answer: B) Cytoplasm
2. End product of glycolysis is:
Answer: B) Pyruvate
3. The energy currency of cell is:
Answer: C) ATP
4. Which cycle releases CO2 during respiration?
Answer: B) Krebs cycle
5. Number of ATP produced from one glucose in aerobic respiration:
Answer: D) 38
6. During anaerobic respiration, the end product is:
Answer: A) Lactic acid/ethanol
7. Krebs cycle takes place in:
Answer: B) Matrix of mitochondria
8. A common intermediate in aerobic and anaerobic respiration is:
Answer: D) Pyruvate
9. Formation of ATP from ADP is called:
Answer: B) Phosphorylation
10. The site of electron transport system is:
Answer: C) Inner mitochondrial membrane
11. Terminal acceptor of electrons in aerobic respiration:
Answer: B) O2
12. CO2 is released in which step of aerobic respiration?
Answer: B) Krebs cycle
13. The first step in respiration:
Answer: C) Glycolysis
14. Respiratory quotient (RQ) for glucose is:
Answer: B) 1
15. Which enzyme catalyzes glucose to glucose-6-phosphate?
Answer: A) Hexokinase
16. The end product of alcoholic fermentation:
Answer: B) Ethanol
17. Number of turns of Krebs cycle per glucose molecule is:
Answer: B) 2
18. Link reaction connects glycolysis & Krebs cycle via:
Answer: A) Acetyl CoA
19. The number of NADH molecules produced from one glucose in glycolysis:
Answer: A) 2
20. FADH2 donates electrons to:
Answer: B) II
21. RQ for fat is:
Answer: A) 0.7
22. First step of glycolysis is catalyzed by:
Answer: A) Hexokinase
23. Which is NOT an intermediate of glycolysis?
Answer: C) Citric acid
24. In anaerobic conditions, pyruvate of plants is converted to:
Answer: B) Ethanol
25. Number of substrate-level phosphorylation steps in glycolysis:
Answer: B) 2
26. Chemiosmotic theory explains:
Answer: A) ATP formation in mitochondria
27. Which is not involved in energy transfer?
Answer: D) Cellulose
28. Final hydrogen acceptor in electron transport chain is:
Answer: C) Oxygen
29. Out of 38 ATP, number formed by oxidative phosphorylation:
Answer: C) 34
30. Net ATP gain from glycolysis:
Answer: A) 2
31. Most ATP is produced in:
Answer: C) Electron transport system
32. Entry of fatty acids for respiration is via:
Answer: B) Beta-oxidation
33. Pyruvate after glycolysis in aerobic respiration is transformed to:
Answer: C) Acetyl CoA
34. The number of molecules of CO₂ produced per turn of Krebs cycle:
Answer: B) 2
35. First step of Krebs cycle:
Answer: A) Citrate formation
36. ATP synthase complex is located in:
Answer: B) Inner mitochondrial membrane
37. Total NADH produced per glucose in Krebs cycle:
Answer: C) 6
38. The enzyme for conversion of pyruvate to ethanol:
Answer: A) Pyruvate decarboxylase
39. Alcoholic fermentation does not release:
Answer: D) Oxygen
40. Final acceptor of electrons in anaerobic fermentation is:
Answer: C) Pyruvate/acetaldehyde
41. Efficiency of aerobic respiration in plants is about:
Answer: B) 35%
42. Which pathway does not involve oxygen?:
Answer: B) Anaerobic glycolysis
43. The mitochondrial stalked particles are also called:
Answer: B) F0-F1 particles
44. Net gain of ATP in lactic acid fermentation:
Answer: A) 2
45. Pasteur effect is related to:
Answer: A) Glycolysis inhibition by O₂
46. Respiratory enzymes are abundant in:
Answer: B) Mitochondria
47. The first compound formed in Krebs cycle by entry of Acetyl CoA:
Answer: B) Citric acid
48. Total ATP from 2 NADH produced in glycolysis (outside mitochondria):
Answer: D) 6
49. Citrate is a 6-carbon compound formed from:
Answer: A) OAA + Acetyl CoA
50. Degradation of fatty acids produces:
Answer: B) Acetyl CoA
51. The direct formation of ATP in metabolism is:
Answer: B) Substrate-level phosphorylation
52. Link enzyme between glycolysis and Krebs cycle is:
Answer: C) Pyruvate dehydrogenase
53. Most active plant tissue for respiration:
Answer: A) Meristem
54. The RQ of organic acid respiration is:
Answer: C) > 1
55. Phosphofructokinase regulates:
Answer: A) Glycolysis
56. Anaerobic respiration in plant root cells may produce:
Answer: B) Ethanol
57. Plant tissue with least respiratory rate:
Answer: C) Seed
58. In glycolysis, ATP consumed in:
Answer: A) 1st & 3rd reactions
59. The RQ of anaerobic respiration is:
Answer: D) ∞
60. In glycolysis, conversion of fructose 6-phosphate to fructose 1,6-bisphosphate uses:
Answer: B) ATP
61. The fate of NADH in anaerobic respiration:
Answer: B) Is reoxidized to NAD+
62. Number of ATPs from 1 molecule of FADH2:
Answer: B) 2
63. Hexose monophosphate (HMP) pathway is significant for production of:
Answer: B) NADPH
64. Respiratory pathway is also termed as:
Answer: B) Catabolic
65. The decarboxylation of pyruvate forms:
Answer: A) CO₂ + Acetyl CoA
66. Glycolysis is also known as:
Answer: A) EMP pathway
67. First stable intermediate in glycolysis:
Answer: B) G6P
68. Glucose is completely oxidized to CO₂ & H₂O in:
Answer: A) Aerobic respiration
69. Number of O₂ molecules consumed per glucose in aerobic respiration:
Answer: C) 6
70. Number of carbon atoms in citric acid:
Answer: C) 6
71. Which is the substrate of first reaction in glycolysis:
Answer: A) Glucose
72. Conversion of malate to oxaloacetate produces:
Answer: B) NADH
73. RQ for succinic acid is:
Answer: A) > 1
74. Respiratory pathway also produces:
Answer: C) Both
75. High RQ (>1) means:
Answer: C) Organic acid respired
76. Complete breakdown of 1 glucose yields how much energy:
Answer: A) 686 Kcal
77. First discovered step of glycolysis was:
Answer: B) Hexose phosphate formation
78. First C₄ acid formed in HMP pathway:
Answer: A) Erythrose 4-phosphate
79. Substrate used for pentose phosphate pathway:
Answer: A) Glucose 6-phosphate
80. The F₀F₁ complex is for:
Answer: B) ATP synthesis
81. ETC components are arranged in:
Answer: B) Increasing redox potential
82. Malate dehydrogenase catalyzes:
Answer: B) Malate to OAA
83. In succinate oxidation, which coenzyme is reduced:
Answer: B) FAD
84. In aerobic respiration, the proton gradient develops across:
Answer: B) Inner membrane
85. Substrate-level phosphorylation occurs in:
Answer: C) Both
86. The largest number of NADH is formed in:
Answer: C) Krebs cycle
87. Fat respiration produces:
Answer: A) More energy
88. Cyanide blocks:
Answer: B) Complex IV
89. Loss of electrons is:
Answer: A) Oxidation
90. The coenzyme in pyruvate dehydrogenase complex:
Answer: D) Thiamine pyrophosphate
91. Product not formed in fermentation:
Answer: C) Oxygen
92. The acceptor of acetyl group in Krebs cycle:
Answer: A) OAA
93. Cyanide inhibits:
Answer: A) Cytochrome oxidase
94. The major site of respiration in seed is:
Answer: B) Embryo
95. Final CO₂ acceptor in respiration:
Answer: D) None (CO₂ is end product)
96. Number of ATPs required for activation of glucose in glycolysis:
Answer: B) 2
97. Enzyme for conversion of pyruvate to acetyl CoA:
Answer: A) Pyruvate dehydrogenase
98. The RQ value is less than 1 if respiratory substrate is:
Answer: B) Fat
99. TCA cycle is called amphibolic because:
Answer: A) Both catabolic/anabolic roles
100. The reason plants respire even in the light:
Answer: A) Need ATP for biosynthesis