NEET MCQs Respiration in Plants [Free PDF Download]

Respiration in Plants is a fundamental chapter in Class 11 Biology that explains how plants break down food to release energy. Unlike animals, plants respire at a cellular level through processes such as glycolysis, the Krebs cycle, and oxidative phosphorylation. This topic is essential for NEET as it builds the foundation of cellular respiration and bioenergetics. Practicing NEET MCQs Respiration in Plants helps students master key concepts like aerobic and anaerobic respiration, energy yield, respiratory quotient (RQ), and the role of mitochondria.

These MCQs are designed to test both factual knowledge and application-based understanding, making them a crucial part of NEET preparation.

NEET MCQs Respiration in Plants

1. In the electron transport system present in the inner mitochondrial membrane, complexes I and IV are
   respectively
   a) NADH Dehydrogenase and FADH2
   b) NADH2 and NADH Dehydrogenase
   c) NADH Dehydrogenase and cytochrome-c oxidase complex
   d) NADH dehydrogenase and ATP synthase
2. In respiration incomplete oxidation of glucose is done under
   a) Aerobic respiration b) Anaerobic respiration
   c) Both (a) and (b) d) None of these
3. The cellular respiration first takes place in the
   a) Cytoplasm b) Golgi bodies c) ER d) Lysosomes
4. Which of the following scientist has given the scheme of glycolysis?
   a) Gustav Embden et. al b) Kreb et. al c) Fritz Lipmann et. al d) None of these
5. Which metabolic pathway is a common pathway to both anaerobic and aerobic metabolism?
   a) Glycolysis b) EMP pathway c) Both (a) and (b) d) None of the above
6. In mitochondria, enzyme cytochrome oxidase is present in
   a) Outer membrane b) Perimitochondrial space
   c) Inner membrane d) Matrix
7. TCA cycle enzymes are present in
   a) Cytoplasm b) Inter membrane space of mitochondria
   c) Mitochondrial matrix d) Inner membrane of mitochondria
8. Among the following, identify the substrate required for the only oxidative reaction that occurs in the
   process of glycolysis.
   a) 3-phosphoglyceric acid
   b) Glyceraldehyde 3-phosphate
   c) Fructose-6-phosphate
   d) Glucose-6-phosphate
9. Aerobic respiration is
   a) The process in which complete oxidation of organic substances in the absence of oxygen
   b) The process in which complete oxidation of organic substances in the presence of oxygen
   c) The process in which incomplete oxidation of organic substances in the absence of oxygen
   d) The process in which incomplete oxidation of organic substances in the presence of oxygen
10. What will happen, when glucose is administered orally?
    a) Excretion b) Digestion c) Circulation d) Respiration
11. How many ATP molecules could maximally be generated from one molecule of glucose, if the complete
    oxidation of one mole of glucose to carbon dioxide and water yields 686 kcal and the useful chemical
    energy available in the high energy phosphate bond of one mole of ATP is 12 kcal?
    a) Two b) Thirty c) Fifty seven d) One
12. In photosynthesis, NADPH2 is formed but in respiration it forms during
    a) HMP b) ETS c) Krebs’ cycle d) None of these

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13.Plants does not need specialised respiratory organ because

a) Each plant part takes care of its own gas exchange
needs
b) Plants do not need great demands for gas
exchange
c) Both (a) and (b) d) None of the above

14. Lactic acid is formed in
    a) Fermentation b) Glycolysis c) HMP pathways d) None of these
15. In which part of mitochondria does ATP synthesis occur?
    a) F1 b) F0
    c) Cristae d) Inner membrane of mitochondria
16. In oxidative decarboxylation, enzyme used to
    a) Pyruvate decarboxylase b) Pyruvate dehydrogenase
    c) Pyruvate hydrogeneticase d) Pyruvate dehydrogeneticase
17. Select the wrong statement.
    a) When tripalmitin is used as a substrate in respiration, the RQ is 0.7
    b) The intermediate compound which links glycolysis with Krebs’ cycle is malic acid
    c) One glucose molecule yields a net gain of 36 ATP molecules during aerobic fermentation
    d) One glucose molecule yields a net gain of 2 ATP molecules during fermentation
18. Enzymes found attached to inner membrane of mitochondria instead of matrix is/are
    a) Succinic Dehydrogenase b) Cytochrome oxidase
    c) Both (a) and (b) d) Malic Dehydrogenase
19. Four respiratory enzymes are given below. Arrange them in increasing order of the carbon number of the
    substrates on which they act.
    I. Enolase
    II. Aconitase
    III. Fumarase
    IV. Alcohol Dehydrogenase
    a) II, IV, III, I b) IV, I, II, III c) I, IV, III, II d) IV, I, III, II
20. Link enzyme in cellular respiration is
    a) Citrate synthetase b) Pyruvate Dehydrogenase
    c) Isocitrate Dehydrogenase d) Succinyl thiokinase
21. Beer and butter milk are products of fermentation by
    a) Rhizopus stolonifer b) Caedobacter taeniospiralis
    c) Bacillus subtilis d) Saccharomyces cerevisiae
22. Apparatus to measure rate of respiration and respiratory quotient is
    a) Auxanometer b) Potometer c) Respirometer d) Manometer
23. Acetyl Co-A binds to oxaloacetic acid to form
    a) Formaldehyde b) Citrate c) Acetate d) Isocitrate
24. In fermentation NADH is oxidised to NAD+ in ….. rate
    a) Fast b) Slow c) Usual d) None of these
25. Last electron acceptor in respiration is
    a) Oxygen b) Hydrogen c) Carbon dioxide d) NADH
26. In animal cells, like muscle, during exercise when O2 is inadequate for cellular respiration, pyruvic acid is
    reduced into lactic acid by
    a) O2 b) Carboxylation
    c) Lactate dehydrogenase d) None of the above
27. Glucose break down takes place ….. in fermentation
    a) Partially b) Completely
    c) According to substrate d) None of these
28. Plants need one of the following for ATP formation
    a) N and P b) N and Cu c) N and Ca d) K
29. First vitamin to be produced through fermentation process using a wild bacterium was

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a) Vitamin-D b) Vitamin-C c) Vitamin- B12 d) Vitamin-B2

30. Fate of pyruvic acid during aerobic respiration is
    a) Lactic acid fermentation b) Alcoholic acid fermentation
    c) Oxidative decarboxylation d) Oxidative phosphorylation
31. In respiration, respiratory substances can be used
    a) Carbohydrate b) Protein c) Organic acid d) All of these
32. In oxidative decarboxylation, only a carbon molecule of pyruvic acid is get oxidised, other two carbon
    molecule goes to form
    a) Acetyl Co-A b) CO2 c) Citric acid d) Both (a) and (b)
33. Enzymes of electron transport system are present in
    a) Inner mitochondrial membrane b) Matrix
    c) Intermembranous space d) Endoplasmic reticulum
34. Fungi are dependent on dead and decaying matter for feeding, it is called
    a) Saprophytes b) Halophytes c) Xerophytes d) Nanophytes
35. Which of the following reaction does not take place in the cell organelle, that is referred to as ‘Power house
    of the cell’?
    a) Glycine Decarboxylation b) Glyceraldehyde 3-phosphate dehydrogenation
    c) Fumaric acid hydration d) Cytochrome oxidation
36. Which of the following is true regarding glycolysis?
    I. Takes place in cytosol
    II. Produces no ATP
    III. Has no connection with electron transport chain
    IV. Reduces two molecules of NAD+ for every glucose molecule processed
    Choose the correct option
    a) Only I b) I, II and III c) I and II d) None of these
37. The reaction which is catalysed by a protein that is not found in the matrix of mitochondria is
    a) Conversion of pyruvic acid to acetyl coenzyme-A b) Oxidative Decarboxylation of 𝛼-ketoglutaric acid
    c) Oxidation of Succinic acid d) Cleavage of Succinyl coenzyme-A
38. All enzymes of TCA cycle are located in the mitochondrial matrix except one, which is located in inner
    mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is
    a) Lactate Dehydrogenase b) Isocitrate Dehydrogenase
    c) Malate Dehydrogenase d) Succinate Dehydrogenase
39. Identify enzyme A in the given reaction of Kreb’s cycle
    OAA+Acetyl Co−A+H2O A → Citric acid + Co – A
    a) Oxaloacetate synthetase b) Citrate synthetase
    c) Aconitase d) Dehydrogenase
40. The enzymes for TCA cycle are present in
    a) Plastids b) Golgi complex
    c) Mitochondria d) Endoplasmic reticulum
41. Which one of the following is the terminal electron acceptor?
    a) Molecular CO2 b) Molecular O2 c) Molecular H2 d) NADPH2
42. In electron transport system, which of the following acts as a final hydrogen acceptor
    a) Oxygen b) Hydrogen c) Calcium d) Ubiquinone
43. If a starving plant is provided with glucose, the rate of respiration would
    a) First rise then fall b) Become constant c) Decrease d) Increase
44. Which one is product of aerobic respiration?
    a) Malic acid b) Ethyl alcohol c) Lactic acid d) Pyruvic acid
45. Given below the diagrammatic presentation of ATP synthesis in mitochondria. Identify A-C and Choose the
    correct option accordingly

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a) A−H+,B−F1,C−F0 b) A−3H+,B−F0,C−F1
c) A−2H+,B−F0,C−F1 d) A−5H+,B−F1,C−F0

46. In Krebs’ cycle,
    a) ADP is converted into ATP
    b) Pyruvic acid is converted into CO2 and H2O
    c) Glucose is converted into CO2
    d) Pyruvic acid is converted into ATP
47. Decline in the activity of the enzyme Hexokinase by glucose-6-phosphate is caused by
    a) Non-competitive
    b) Competitive inhibitors
    c) Allosteric modulators
    d) Denaturation of enzyme
48. In which of the following reactions of glycolysis, oxidation takes place?
    a) Glucose 6-PO4 to fructose 6-PO4
    b) Glyceraldehydes 3-phosphate to 1, 3-diphosphoglycerate
    c) 1,3-diphosphoglycerate to 3-phosphoglycerate
    d) 2-phosphoglycerate to phosphoglycerate
49. During conversion of pyruvic acid into acetyl Co-A, pyruvic acid is
    a) Oxidized b) Reduced c) Isomerized d) Condensed
50. During anaerobic respiration in yeast
    a) 𝐻2𝑂 and 𝐶𝑂2 are end-products
    b) 𝐶𝑂2 , ethanol and energy are end-products
    c) 𝐶𝑂2 , and H2O are end-products
    d) 𝐶𝑂2 , acetic acid and energy are end-products
51. Choose the correct combination of A and B according to NCERT text book.
    All living organisms need …A… for carrying out daily life activities and is obtained by …B… of
    macromolecules
    a) A-oxygen; B-reduction b) A-energy; B-reduction
    c) A-energy; B-oxidation d) A-oxygen; B-oxidation
52. Most of the biological energy is supplied by mitochondria through
    a) Breaking of proteins b) Reduction of NADP+
    c) Breaking of sugars d) Oxidising TCA (tricarboxylic acid) substrate
53. Chemiosmotic mechanism of ATP production in aerobic respiration was given by
    a) Krebs b) Calvin c) Hatch and Slack d) Peter Mitchell
54. Choose the correct combination of labeling the molecules involved in the pathway of anaerobic respiration
    in yeast

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a) A – Ethanol, B – CO2 , C – Acetaldehyde
b) A – CO2 , B – Ethanol, C- Acetaldehyde
c) A – CO2, B – Acetaldehyde, C- Ethanol
d) A – Ethanol, B – Acetaldehyde, C – CO2

55. Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and
    proteins?
    a) Glucose-6-phosphate b) Fructose, 6-bisphosphate
    c) Pyruvic acid d) Acetyl Co-A
56. In succulent plants like Opuntia, the RQ value will be
    a) Less than one b) More than one c) Infinite d) Zero
57. The pyruvic acid formed during glycolysis is oxidized to CO2 and H2O in a cycle called
    a) Calvin cycle b) Nitrogen cycle c) Hill reaction d) Krebs’ cycle
58. Respiratory enzymes are present in the following organelle
    a) Peroxisome b) Chloroplast c) Mitochondrion d) Lysosome
59. An ATP molecule is structurally most similar to a molecule of
    a) RNA nucleotide b) DNA nucleotide c) Amino acid d) Fatty acid
60. Read the following and choose the option containing correct pair
    I. DCMU Herbicide Inhibitor of non-cyclic electron transport
    II. PMA Fungicide Reduce transpiration
    III. Colchicine Alkaloid Causes male sterility
    IV. Soilrite Sodium alginate Encapsulation of somatic embryos
    a) I and II b) I and III c) II and III d) II and IV
61. Oxidation of one molecule of NADH gives rise to
    a) 3 ATP molecules b) 12 ATP molecules c) 2 ATP molecules d) 1ATP molecule
62. Aerobic respiratory pathway is appropriately termed as
    a) Catabolic b) Parabolic c) Amphibolic d) Anabolic
63. In alcohol fermentation,
    a) There is no electron donor
    b) Oxygen is the electron acceptor
    c) Triose phosphate is the electron donor, while acetaldehyde is the electron acceptor
    d) Triose phosphate is the electron donor, while pyruvic acid is the electron acceptor
64. In respiration breaking down of glucose with oxygen is known as
    a) Oxidation process b) Reduction process
    c) Oxidation-oxaloacitation process d) All of the above
65. Net gain of ATP molecules per hexose during aerobic respiration is
    a) 12 b) 18 c) 36 d) 30
66. Which of these are respiratory poisons or inhibitors of electron transport chain?
    a) Cyanides b) Antimycin-A c) Carbon monoxide d) All of these
67. Kreb’s cycle is completed with the formation of
    a) Citric acid b) Oxaloacetic acid (OAA)
    c) Succinic acid d) Malic acid

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68. Where is ATP synthesised in glycolysis?
    a) When 1, 3 di PGA is changed into 3PGA
    b) When glucose is converted into glucose-6-phosphate
    c) Both (a) and (b)
    d) When, 1, 6 diphosphate is broken in triose phosphate
69. Maximum number of ATP is obtained from
    a) Glucose b) Palmitic acid c) Malic acid d) 𝛽-amino acid
70. Glycolysis takes place in
    a) All living cells b) Eukaryotic cells only
    c) Prokaryotic cells only d) None of these
71. Krebs’ cycle begins with the reaction
    a) Citric acid +acetyl Co-A b) Oxaloacetic acid + pyruvic acid
    c) Oxaloacetic acid + citric acid d) Oxaloacetic acid + acetyl Co-A
72. Co-Factor required for formation of acetyl Co-A is
    a) TPP b) Lipoic acid c) Mg2+, Co-A d) All of these
73. In anaerobic respiration in plants
    a) Oxygen is absorbed b) Oxygen in released
    c) Carbon dioxide is released d) Carbon dioxide is absorbed
74. The respiratory quotient (RQ) of some of the compounds are 4,1 and 0.7. These compounds are identified
    respectively as
    a) Malic acid, palmitic acid and tripalmitin b) Oxalic acid, carbohydrate and tripalmitin
    c) Tripalmitin, malic acid and carbohydrate d) Palmitic acid, carbohydrate and oxalic acid
75. The enzyme ….. is used to catalysed when condensation of acetyl group with oxaloacetic acid and to yield
    citric acid
    a) Citrate permeate b) citrate synthase c) Citrate burate d) Citrate maliate
76. The respiratory quotient (RQ) of a germinating castor seed is
    a) Equal to one b) Greater than one c) Less than one d) Equal to zero
77. Glycolysis
    I. causes partial oxidation of glucose (one molecule) to form 2-molecules of pyruvic acid and 2 ATP as net
    gain
    II. takes place in all living cells
    III. uses 2 ATP at two steps
    IV. scheme was given by Gustav Embden, Otto Mayerhof and J Parnas
    Choose the correct option containing appropriate statements from the above
    a) I, II and III b) I, II and IV c) I, II, III and IV d) Only I
78. During oxidative phosphorylation, the net gain of ATP is
    a) 40 b) 38 c) 34 d) 30
79. Decarboxylation is involved in
    a) Electron transport system
    b) Glycolysis
    c) Krebs’ cycle
    d) Lactic acid fermentation
80. Alternate name of TCA cycle is
    a) Kreb’s cycle b) Grab’s cycle c) Mayerhoff cycle d) Embden cycle
81. A businessman of 80 kg weight requires 4800 kcal energy daily. How many ATP molecules and glucose
    molecules does he require to produce this much energy?
    a) 20 molecules of glucose and 384 molecules of ATP
    b) 40 molecules of glucose and 264 molecules of ATP
    c) 18 molecules of glucose and 657 molecules of ATP
    d) 20 molecules of glucose and 460 molecules of ATP

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82. Which one of the following pairs is wrongly matched?
    a) Methanogens – Gobar gas b) Yeast – Ethanol
    c) Streptomycetes – Antibiotic d) Coliforms – Vinegar
83. In hurdle race, which of the following is accumulated in the leg muscle?
    a) Performed ATP b) Glycolysis c) Lactate d) Oxidative metabolism
84. During the exercise, pyruvic acid is reduced to
    a) Lactic acid b) Fumaric acid c) Glutamic acid d) Oxaloacetic acid
85. The compounds which are oxidised during respiration are known as
    a) Respiratory substrates b) Oxalo acid
    c) TCA cycle d) None of these
86. Refer the given equation
    2(C51H98O6)+145 O2→102 CO2+98 H2O+ Energy
    The respiratory quotient in this case is
    a) 1 b) 0.7 c) 1.45 d) 1.62
87. Energy required for life processes is obtained by
    a) Oxidation b) Reduction c) Deduction d) Antilation
88. Choose the correct statement for the given options
    a) Intermediates in the pathway are utilised to synthesise other compounds
    b) No alternative substrates other than glucose is allowed to enter the pathway at intermediate stages
    c) None of the substrate is respired in the pathway at intermediary stages
    d) Pathway functioning is insequential
89. In plants, glucose is derived from which of the following?
    a) Protein b) Fat c) Oxalic acid d) Sucrose
90. The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine
    triphosphate (ATP) is formed because
    a) High energy bonds are formed in mitochondrial
    proteins
    b) ADP is pumped out of the matrix into the
    intermembrane space
    c) A proton gradient forms across the inner
    membrane
    d) There is a change in the permeability of the inner
    mitochondrial membrane towards adenosine
    diphosphate (ADP)
91. The process by which there is inhibition of aerobic respiration by atmospheric oxygen is
    a) Pasteur’s effect b) Calvin’s effect c) Darwin’s effect d) None of these
92. More carbon dioxide is evolved than the volume of oxygen consumed when the respiratory substrate is
    a) Fat b) Sucrose c) Glucose d) Organic acid
93. Anaerobic respiration is also called as
    a) 𝛽-oxidation b) Fermentation c) Oxidation d) None of these
94. The main purpose of cellular respiration is to
    a) Convert potential energy to kinetic energy
    b) Convert kinetic energy to potential energy
    c) Create energy in the cell
    d) Convert energy stored in the chemical bonds of glucose to an energy that the cell can use
95. Which of the following substances yield less than 4 kcal/mol when its phosphate bond is hydrolysed?
    a) Creatine phosphate b) ADP c) Glucose-6-phosphate d) ATP
96. Five gram mole of glucose on complete oxidation releases
    a) 3430 kcal of energy b) 343 kcal of energy c) 2020 kcal of energy d) 430 kcal of energy
97. NADP, NAD and FAD are acceptors of
    a) Phosphate b) Electrons c) Oxygen d) Hydrogen
98. How many PGAL are produced by glycolysis of 3 molecules of glucose? How many ATP are released by
    respiration of these PGAL till formation of CO2 and H2O?
    a) 4 PGAL- 80 ATP b) 6 PGAL-160ATP c) 4 PGAL-40ATP d) 6 PGAL-120ATP

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99. Identify the specific group, which carries out the following biochemical reaction:
    Aspartic acid+𝛼-ketoglutaric acid →Oxaloacetic acid+Glutamic acid
    a) Synthetases b) Peptidases c) Transaminases d) Lyases
100. Which of following is connecting link between glycolysis and Krebs’ cycle?
     a) Pyruvic acid
     b) Isocitric acid
     c) Acetyl Co-A
     d) Phosphoglyceric acid
101. Which one of the following reactions is an example of oxidative Decarboxylation?
     a) Conversion of succinate to fumarate b) Conversion of fumarate to malate
     c) Conversion of pyruvate to acetyl Co-A d) Conversion of citrate to isocitrate
102. If O2 is not present, yeast cells break down glucose to
     a) CO2+H2O b) CO2+ Lactic acid c) C2H5OH+H2O d) C2H5OH and CO2
103. How many ATP is released respectively when NADH and FADH2 molecules get oxidised?
     a) 3 ATP, 2 ATP b) 2 ATP, 3 ATP c) 5 ATP, 4 ATP d) 3 ATP, 5 ATP
104. Release of energy by breaking down of C-C bond of various organic molecules by oxidation process for
     cellular use is known as
     a) Respiration b) Photorespiration
     c) Oxidative phosphorylation d) Combustion
105. Krebs’ cycle was discovered by Krebs in pigeon muscles in 1940. Which step is called gateway step/link
     reaction/transition reaction in respiration?
     a) Glycolysis b) Formation of acetyl Co-A
     c) Citric acid formation d) ETS terminal oxidation
106. Correct sequence of electron acceptor of ATP synthesis is
     a) cyt-a, a3 , b, c b) cyt-b, c ,a, a3 c) cyt-b, c , a3, a d) cyt-c, b, a, a3
107. The number of ATP produced when a molecule of glucose undergoes fermentation
     a) 4 b) 36 c) 2 d) 38
108. Oxidative decarboxylation is
     a) Pyruvic acid is oxidised to carbon dioxide b) Pyruvic acid is subsidised to oxygen
     c) Pyruvic acid is oxidised to oxygen d) Pyruvic acid is subsidised to carbon dioxide
109. An example of Pasteur’s effect is
     a) 𝑃𝑒𝑛𝑖𝑐𝑖𝑙𝑙𝑖𝑢𝑚 b) 𝑃𝑖𝑛𝑛𝑢𝑙𝑎𝑟𝑖𝑎 c) 𝑆𝑎𝑐𝑐ℎ𝑎𝑟𝑜𝑚𝑦𝑐𝑒𝑠 d) 𝑁𝑜𝑠𝑡𝑜𝑐
110. Fermentation is
     a) Anaerobic respiration b) Incomplete oxidation of carbohydrate
     c) Complete oxidation of carbohydrate d) None of the above
111. Citric acid cycle is the alternate name of which of the following?
     a) HMP shunt b) Glycolysis c) TCA cycle d) Calvin cycle
112. When one molecule of glucose is completely oxidized during aerobic respiration, how many molecules of
     carbon dioxide are released due to Tricarboxylic acid cycle?
     a) One b) Two c) Three d) Four
113. Fat prior to its oxidation associate with
     a) Cyclic AMP b) Co-A c) GMP d) ATP
114. The RQ value of oxalic acid is
     a) 1.0 b) 0.7 c) 4 d) ∝
115. Energy currency of cell is
     a) Mitochondria b) Chloroplast c) ATP d) Glucose
116. Break down process is also called
     a) Catabolism b) Anabolism c) Both (a) and (b) d) All of these
117. The energy-releasing metabolic process in which substrate is oxidized without an external electron
     acceptor, is called

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a) glycolysis b) Fermentation c) Aerobic respiration d) Photorespiration

118. How many times ATP is utilised in glycolysis?
     a) 2 b) 3 c) 4 d) 5
119. Aerobic respiration takes place in
     a) Mitochondria b) Ribosome c) Glogi body d) Both (a) and (b)
120. Sequence of events in Kreb’s cycle is
     a) Acetyl Co-A → Citrate → Pyruvate → Oxaloacetic acid ← fumarate ← Malate ← Succinate 𝛂
     ketoglutaralte
     b) Acetyl Co-A → Citric acid → 𝛂-ketoglutarate acid → Oxaloacetic acid ← Malic acid ← Fumaric acid ←
     Succinic acid
     c) Acetyl Co-A → Citric acid → Malic acid Oxaloacetic ← Oxaloacetic acid Succinic ← 𝛂-ketoglutaric acid ←
     d) All are wrong
121. Which of the following is a 4-carbon compound?
     a) Oxaloacetic acid b) Phosphoglyceric acid
     c) Ribulose bisphosphate d) Phosphoenol pyruvate
122. An example of non-competitive inhibition is
     a) The inhibition of succinic Dehydrogenase by
     Malonate
     b) Cyanide action on cytochrome oxidase
     c) Sulpha drug on folic acid synthesizing bacteria d) The inhibition of Hexokinase by glucose 6
     phosphate
123. What is the net ATP molecules gain, when 4 molecules of glucose undergo anaerobic respiration in plant?
     a) 8 ATP b) 20 ATP c) 144 ATP d) 16 ATP
124. Chemiosmosis hypothesis given by Peter Mitchell proposes the mechanism of
     a) Synthesis of NADH b) Synthesis of ATP c) Synthesis of FADH2 d) Synthesis of NADPH
125. Glycolysis
     a) Takes place in the mitochondria
     b) Produces no ATP
     c) Has no connection with electron transport chain
     d) Reduce two molecules of NAD+ for every glucose molecule processed
126. Citric acid cycle is also known as
     a) Tricarboxylic acid cycle b) Oxidative decarboxylation
     c) Fermentation cycle d) Both (a) and (b)
127. Instantaneous source of energy is
     a) Protein b) Lipid c) Fats d) Glucose
128. Before entering into the respiratory pathway fats breakdown into
     a) Fatty acid and glycerol b) Fatty acid and ascorbic acid
     c) Fatty acid and ascorbic acid d) Fatty acid and amino acid
129. In which of the following reactions of glycolysis, a molecule of water is removed from the substrate?
     a) Fructose-6-phosphate → Fructose-1, 6
     bisphosphate b) 3-phosphate-glyceraldehyde → 1, 3
     bisphosphoglyceric acid
     c) PEP → Pyruvic acid d) 2- phosphoglycerate → PEP
130. The reactions of Pentose Phosphate Pathway (PPP) take place in
     a) Mitochondrion b) Cytoplasm
     c) Chloroplast, peroxisome and mitochondrion d) Chloroplast, glyoxysome and mitochondrion
131. In citric acid cycle first step is
     a) Acetyl Co-A combines with oxalo acetic acid b) Acetyl Co-A combines with citric acid
     c) Citric acid combines with oxaloacetic acid d) Citric acid combines with malic acid
132. Pyruvate →C2H3OH+CO2
     The above reaction needs two enzymes named as
     a) Pyruvate decarboxylase and alcohol dehydrogenase

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b) Pyruvate decarboxylase and enolase
c) Pyruvate decarboxylase and pyruvate kinase
d) Pyruvate carboxylase and aldolase

133. FAD is electron acceptor during oxidation of which of the following?
     a) 𝛼-ketoglutarate→Succinyl Co-A b) Succinic acid → Fumaric acid
     c) Succinyl Co-A → Succinic acid d) Fumaric acid → Malic acid
134. Which of the following substrate can enter into the respiration?
     a) Glucose b) Amino acid c) Fatty acid d) All of these
135. RQ value of 4 may be expected for the complete oxidation of which one of the following?
     a) Glucose b) Malic acid c) Oxalic d) Tartaric acid
136. When act as a respiratory substrate, which of the following would be broken down to acetyl Co-A?
     a) Fatty acid b) Protein c) Carbohydrate d) All of these
137. Anaerobic respiration generally occurs in
     a) Lower organism, e.g., bacteria and fungi b) Higher organism, e.g., animal
     c) Both (a) and (b) d) None of the above
138. In which of the following, reduction of NAD does not occur?
     a) Isocitric acid→𝛼-ketoglutaric acid
     b) Malic acid →Oxaloacetic acid
     c) Pyruvic acid →Acetyl coenzyme
     d) Succinic acid →Fumaric acid
139. How many NADH + H+ molecule is released in Kreb’s cycle?
     a) 3 b) 6 c) 12 d) 14
140. Cell respiration is carried out by
     a) Ribosome b) Mitochondria c) Chloroplast d) Golgi bodies
141. The released energy obtained by oxidation is stored as
     a) A concentration gradient across a membrane b) ADP
     c) ATP d) NAD+
142. Respiratory Quotient (RQ) is one in case of
     a) Fatty acids b) Nucleic acids c) Carbohydrates d) Organic acids
143. Which of the following substrates is used in the formation of alcohol?
     a) Sucrose b) Glucose c) Galactose d) Fructose
144. Which one is correct sequence in glycolysis?
     a) G-6-P→PEP → 3-PGAL → 3-PGA b) G-6-P→3-PGAL → 3-PGA → PEP
     c) G-6-P→PEP → 3-PGA → 3-PGAL d) G-6-P→3-PGA →3-PGAL → PEP
145. Cyanide resistant pathway is
     a) Anaerobic respiration b) Aerobic respiration
     c) Both (a) and (b) d) None of these
146. Common enzyme in glycolysis and pentose phosphate pathway is
     a) Hexokinase b) aconitase c) Fumarase d) Dehydrogenase
147. In aerobic respiration complete oxidation of pyruvate by the stepwise removal of all the hydrogen atom
     makes …….. molecule of CO2
     a) 2 b) 3 c) 4 d) 5
148. Phase common in aerobic and anaerobic respiration is
     a) TCA cycle b) Glycolysis c) Glycogenolysis d) ETS
149. 2NADH(H+) produced during anaerobic glycolysis yield
     a) 6 ATP molecules b) 4 ATP molecules c) 8 ATP molecules d) None of these
150. In the production of ethanol, pyruvic acid is first converted to acetaldehyde by the enzyme.
     a) Alcohol Dehydrogenase b) Alcohol oxidase
     c) Pyruvate Dehydrogenase d) Pyruvate decarboxylase
151. The activity of succinate Dehydrogenase is inhibited by

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a) Pyruvate b) Glycolate c) Melonate d) Phosphoglycerate

152. Citric acid is industrially best produced by
     a) Streptococcus lactis b) Aspergillus niger
     c) Penicillium purpurogenum d) Lactobacillus delbreukii
153. Respiratory substrate are the organic substance which are ….. during respiration to liberate energy
     a) Oxidised b) Reduced c) Both (a) and (b) d) Synthesised
154. The oxidation of pyruvic acid to CO2 and H2O is called
     a) Fermentation b) Citric acid cycle
     c) Glycolysis d) Oxidative phosphorylation
155. Preparatory phase before fermentation is
     a) Upstream process b) Downstream process c) Inoculation d) Filtration
156. For retting of jute the fermenting microbe used is
     a) Helicobactor pylori b) Methophilic bacteria
     c) Streptococcus lactis d) Butyric acid bacteria
157. The respiratory quotient during cellular respiration would depend on the
     a) Nature of enzymes involved b) Nature of the substrate
     c) Amount of carbon dioxide released d) Amount of oxygen utilized
158. Which one of following is complex V of the ETS of inner mitochondrial membrane?
     a) NADH Dehydrogenase b) Cytochrome oxidase
     c) Ubiquinone d) ATP synthase
159. Protein directly cannot be used as a respiratory substrate, it breaks down into
     a) Amino acid b) Fatty acid c) Glycolytic acid d) Fumaric acid
160. Ethyl alcohol is commercially manufactured from
     a) Bajra b) Grapes c) Maize d) Sugarcane
161. Biological oxidation in Krebs’ cycle involves
     a) O2 b) CO2 c) O3 d) NO2
162. Last electron acceptor during ETS is
     a) O2 b) cyt-a c) cyt-a2 d) cyt-a3
163. Which enzyme converts glucose into alcohol?
     a) Zymase b) Diastase c) Invertase d) Lipase
164. Glycolysis is a part of
     a) Anaerobic respiration only b) Aerobic respiration only
     c) Both (a) and (b) d) Krebs’ cycle
165. When tripalmitin is used as a substrate in respiration, the RQ is
     a) >1 b) 1.0 c) 0.9 d) 0.7
166. Read the following table and choose the correct pair.
     V. DCMU Herbicide Inhibitor of non-cyclic electron transport
     VI. PMA Fungicide Reduce transpiration
     VII. Colchicine Alkaloid Causes male sterility
     VIII. Soilrite Sodium alginate Encapsulation of somatic embryos
     a) I, II b) I, III c) II, III d) II, IV
167. In aerobic respiration removal 3 molecules of CO2 occurs in
     a) Matrix of the mitochondria b) Inner membrane of the mitochondria
     c) Both (a) and (b) d) Anywhere in the mitochondria
168. In anaerobic respiration bacteria produce
     a) Lactic acid b) Formic acid c) Acetic acid d) Glutamic acid
169. During its formation, bread becomes porous due to release of Carbon dioxide by the action of
     a) Yeast b) Bacteria c) Virus d) Protozoans
170. Before entering respiratory pathway amino acids are
     a) Decarboxylated b) Hydrolysed c) Deaminated d) Phosphorylated

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171. The intermediate compound common for aerobic and anaerobic respiration is
     a) Citric acid b) Pyruvic acid c) Acetyl Co-A d) Succinic acid
172. How many ATP molecules are obtained from fermentation of 1 molecule of glucose?
     a) 2 b) 4 c) 3 d) 5
173. During which stage in the complete oxidation of glucose are the greatest number of ATP molecules formed
     from ADP?
     a) Conversion of pyruvic acid to acetyl Co-A b) Electron transport chain
     c) Glycolysis d) Krebs’ cycle
174. In plants the cells in the interior parts are
     a) Dead and for mechanical support b) Live and for various purpose
     c) Both (a) and (b) d) None of the above
175. Ultimate source of energy in biosphere, is
     a) Sunlight b) Protein c) Fats d) Enzymes
176. Dough kept overnight in warm weather becomes soft and spongy because of
     a) Absorption of carbon dioxide from atmosphere b) Fermentation
     c) Cohesion d) Osmosis
177. The respiratory quotient (RQ) or respiratory ratio is
     a) RQ = Volume of O2 evolved
     Volume of CO2 consumed b) RQ =Volume of O2 consumed
     Volume of CO2 evolved
     c) RQ =Volume of CO2 consumed
     Volume of O2 evolved d) RQ =Volume of CO2 evolved
     Volume of O2 consumed
178. Maximum amount of energy/ATP is liberated on oxidation of
     a) Fats b) Proteins c) Starch d) Vitamins
179. NADH2→FAD→FADH2
     The given reaction occurs in
     a) Heart cells b) Kidney cells c) Liver cells d) Nerve cells
180. Net yield of ATP molecules in aerobic respiration during Krebs’ cycle per glucose molecule is
     a) 2 ATP molecules b) 8 ATP molecules
     c) 36 ATP molecules d) 38 ATP molecules
181. Respiratory quotient can very due to
     a) Temperature b) Respiratory substrate
     c) Light and oxygen d) Respiratory product
182. In anaerobic respiration the correct sequence of catabolism of glucose is
     a) Glycolysis, TCA cycle, oxidative phosphorylation
     b) Glycolysis, fermentation
     c) Glycolysis, oxidative phosphorylation, TCA cycle
     d) Oxidative phosphorylation, TCA cycle, glycolysis
183. In eukaryotes, photosynthesis occurs in
     a) Chloroplast b) Stomatal opening c) Bark d) Roots
184. In yeast during anaerobic respiration, how many glucose molecules are required for production of 38 ATP
     molecules?
     a) 1 b) 2 c) 19 d) 38
185. Which of the following is involved in the catalysis of link reaction during aerobic during aerobic
     respiration?
     a) Vitamin- A b) Vitamin- B1 c) Vitamin- B6 d) Vitamin- K
186. Respiratory quotient in anaerobic respiration is
     a) 0.7 b) 0.9 c) Unity d) Infinity
187. Choose the correct combination of A and B in accordance with the NCERT text book.
     The NADH synthesised in …A… is transferred into the mitochondria and undergoes oxidative …B…
     a) A-EMP; B-carboxylation b) A-ETS; B-phosphorylation

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c) A-glycolysis; B-phosphorylation d) A-TCA cycle; B-decarboxylation

188. Total gain of ATP molecules during aerobic respiration of one molecule of glucose
     a) 36 b) 38 c) 40 d) 34
189. Which of the following enzyme is responsible for formation of glucose from glucose-6-phosphate?
     a) Kinase b) Aldolase c) Dehydrogenase d) Phosphatase
190. Alcoholic fermentation takes place in the presence of
     a) Maltase b) Zymase c) Amylase d) Invertase
191. Which of these steps in Krebs’ cycle indicates substrate level phosphorylation?
     a) Conversion of succinyl acid to ∝-ketoglutaric acid
     b) Conversion of succinic acid to malic acid
     c) Conversion of succinyl Co-A to succinic acid
     d) Conversion of malic acid to oxalo acetic acid
192. Identify 𝐴 and 𝐵 in the given reaction
     Pyruvic acid
     +Co-A +NAD+ Mg2+ → Pyruvate dehydrogenase
     A+B+NADH+H+
     a) A-PEP; B-CO2 b) A-Acetyl Co-A; B-CO2
     c) A-CO2; B-H2O d) A-Acetyl Co-A; B-H2O
193. In which one of the following reactions, oxidative Decarboxylation does not occur?
     a) Malic acid → Pyruvic acid b) Pyruvic acid → Acetyl Co-A
     c) Glyceraldehyde 3-phosphate → 1, 3
     bisphosphoglycolysis acid d) 𝛼-ketoglutaric acid → Succinyl Co-A
194. Anaerobic respiration can occur
     a) Lower organism b) Higher plants and animals
     c) Both (a) and (b) d) None of the above
195. The three boxes in this diagram represent the three major biosynthetic pathways in aerobic respiration.
     Arrows represent net reactants or products

The numbered 2, 2, 6 can all be
a) NADH b) ATP c) H2O d) FAD2 or FADH2

196. The main purpose of electron transport chain is to
     a) Cycle NADH + H+ back to NAD+ b) Use the intermediate from TCA cycle
     c) Breakdown pyruvic acid d) All of the above
197. How many ATP are formed during the citric acid cycle?
     a) 12 b) 24 c) 32 d) 35
198. RQ is always less than one in
     a) Wheat b) Millets c) Bean d) Castor
199. In glycolysis from glucose to pyruvic acid involves more than seven reaction. Each individual reaction
     needs
     a) One molecule of ATP b) One molecule of ADP
     c) One molecule of NAD d) One molecule of specific enzyme
200. Which one is true for ATP?
     a) ATP is prosthetic part of an enzyme b) ATP is an enzyme
     c) ATP is organic ions of enzyme d) ATP is a coenzyme
201. Oxidative phosphorylation refers to
     a) Anaerobic production of ATP b) The citric acid cycle production of ATP
     c) Production of ATP by chemiosmosis d) Alcoholic fermentation

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202. Which one is not correct about Krebs’ cycle?
     a) It is also called citric acid cycle
     b) The intermediate compound which links glycolysis with Krebs’ cycle is malic acid
     c) It occurs in mitochondria
     d) It starts with six carbon compound
203. Which specialised cell provides interconnectivity for air spaces?
     a) Parenchyma b) Chlorenchyma c) Sclerenchyma d) None of these
204. Steps of respiration are controlled by
     a) Substrates b) Enzymes c) Hormone d) Bile juice
205. The similarity between NAD+ and NADP+ is that
     a) Take up electron at a time b) Take up two protons at a time
     c) Take up two electrons at a time d) Give up one protons at a time
206. The following is a simplified scheme showing the fate of glucose during aerobic and anaerobic respiration.
     Identify the end products that are formed at stages indicated as A, B, C and D. identify the correct option
     from these given below. a) 1. Carbon dioxide and water, B- Pyruvic acid, C- Ethyl alcohol and carbon dioxide, D- lactic acid
     b) 1. Pyruvic acid, B- Carbon dioxide and water, C- Lactic acid , D- Ethyl alcohol and carbon
     dioxide
     c) 1. Pyruvic acid, B- Carbon dioxide and water, C- Ethyl alcohol and carbon dioxide, D- Lactic
     acid
     d) 1. Pyruvic acid, B- Ethyl alcohol and carbon dioxide, C- Lactic acid, D- Carbon dioxide and
     water
207. The process by which ATP is produced in the inner membrane of a mitochondrion, the electron transport
     system transfers protons from the inner compartment to the outer, as the protons flow back to the inner
     compartment, the energy of their movement is used to add phosphate to ADP, forming ATP is
     a) Chemiosmosis b) Phosphorylation c) Glycolysis d) Fermentation
208. The haem protein complexes, which act as oxidizing agents are known as
     a) Haemoglobin b) Myoglobin c) Chlorophyll d) Cytochrome
209. If RQ is 0.6 in a respiratory metabolism, it would mean that
     a) Carbohydrates are used as respiratory substrate b) Organic acids are used as respiratory substrate

c)
The oxidation of the respiratory substrate
consumed more oxygen than the amount of CO2
released
d) The oxidation of respiratory substrate consumed
less oxygen than the amount of CO2 released

210. The flowchart given below shows the steps in glycolysis. Select the option that correctly fills in the missing
     steps A, B, C and D
     a) A-Fructose-6-phosphate, B-Fructose-1, 6-biphosphate, C-3-PGAL, D-1, 3-biphosphoglyceric acid
     b) A-Fructose-1, 6-biphosphate, B-3-PGAL, C-1, 3-biphosphoglyceric acid, D-3-PGA
     c) A-3-PGA, B-1, 3-biphosphoglyceric acid, C-3-PGAL, D-Fructose-1, 6-biphosphate
     d) A-Fructose-1, 6-biphosphate, B-Fructose-6-biphosphate, C-3-PGAL, D-1, 3-biphosphoglyceric acid
211. A scientist added a chemical (cyanide) to an animal cell to stop aerobic respiration. Which of the following
     is most likely to have been affected by this treatment?
     a) Active transport of substances across the plasma membrane
     b) Passive transport of substances across the plasma membrane
     c) Diffusion of substances across the plasma membrane
     d) The thickness of the plasma membrane
212. Wine and beer are produced directly by fermentation. Brandy and whisky require both fermentation and
     distillation because
     a) Fermentation is inhibited at an alcohol level of 10-18%
     b) Distillation prolongs storage
     c) Distillation improves quality
     d) Distillation purifies the beverage
213. For gaseous exchange plants have
     a) Stomata
     b) Lenticels
214. Citric acid cycle was discovered by
     a) Hans Krebs’; 1937
     b) Jon Mathai; 1937
     c) Pores
     c) Parna; 1936
215. Vitamin-C was the first vitamin to be produced by a fermentation process using
     a) Penicillium
     b) E. coli
     c) Yersinia pestis
216. Net gain of ATP from one molecule of glucose in glycolysis, is
     a) 3
     b) 6
217. In Krebs’ cycle, GTP is formed in
     a) Oxidative phosphorylation
     c) 8
     d) Both (a) and (b)
     d) Embeden; 1936
     d) Acetobacter
     d) 2
     b) Substrate level phosphorylation
     c) Photophosphorylation
218. A competitive inhibitor of Succinic Dehydrogenase is
     a) Malonate
     b) Oxaloacetate
     d) Decarboxylation
     c) 𝛼-ketoglutarate
     d) Malate
219. The net gain of ATP from complete oxidation of one molecule of glucose in eukaryote is
     a) 2
     b) 4
220. Animals are
     a) Heterotrophic
     b) Autotrophic
     c) 24
     c) Both (a) and (b)
     d) 36
     d) None of these
221. During Kreb’s cycle of …A… NADH, …B… ATP is produced through ETS in mitochondria. Choose, the
     correct pair from the option given below
     P a ge| 15

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a) A-2; B-4 b) A-4; B-2 c) A-6, B-18 d) A-2; B-8

222. Product of glycolysis is
     a) Citric acid
     b) Dihydroxy acetone
     c) Pyruvic acid
     d) Phosphoenol pyruvate
223. Electron Transport System (ETS) occurs in
     a) Inner mitochondrial membrane b) Outer mitochondrial membrane
     c) Both (a) and (b) d) Not specific place
224. In aerobic respiration, citric acid cycle takes place in
     a) Cytosol b) Mitochondria
     c) Peroxisome d) Endoplasmic reticulum
225. If RQ is less than 1.0 in a respiratory metabolism, it would mean that
     a) Carbohydrates are used as respiratory substrate
     b) Organic acids are used as respiratory substrate
     c) The oxidation of the respiratory substrate consumed more oxygen than the amount of CO2 released
     d) The oxidation of the respiratory substrate consumed less oxygen than the amount of CO2 released
226. Calorie is the unit of
     a) Sound b) Temperature c) Light d) Heat
227. Which of the following organism is useful in the preparation of Roquefort cheese?
     a) Mucor b) Rhizopus c) Aspergillus d) Penicillum
228. What is the correct order of the stages of cellular respiration?
     a) Krebs’ − Electron − Glycolysis cycle transport chain
     b) Electron − Krebs’ cycle − Glycolysis transport chain
     c) Glycolysis −Krebs’ cycle − Electron transport chain
     d) Glycolysis − Electron transport chain − Krebs’ cycle
229. The term glycolysis has originated from the Greek word ….. and ….
     a) Glycos, lysis b) Glycol, analysis c) Glycerol, lysis d) Glycol, lysis
230. The organelle associated with aerobic respiration is
     a) Chloroplast b) Centriole c) Nucleus d) Mitochondria
231. Incomplete breakdown of sugar in anaerobic respiration forms
     a) Glucose and carbon dioxide b) Alcohol and carbon dioxide
     c) Water and carbon dioxide d) Fructose and water
232. The total energy trapped per gm mole of glucose is 1292 kJ with on efficiency of
     a) 35% b) 55% c) 45% d) 25%
233. Phase common in aerobic and anaerobic respiration is
     a) Krebs’ cycle b) Glycolysis c) Glycogenolysis d) ETS
234. Synthesis process in organism is also called
     a) Catabolism b) Anabolism c) Both (a) and (b) d) None of these
235. Oxalosuccinic acid, an intermediary compound of Krebs’ cycle is a
     a) 5-carbon compound b) 6-carbon compound c) 4-carbon compound d) 3-carbon compound
236. Which of the following process takes place in mitochondria?
     a) Photolysis b) Photophosphorylation
     c) Carboxylation d) Oxidative phosphorylation
237. How much percentage of energy is released during lactic acid and alcoholic of fermentation?
     a) 2 b) 9 c) 8 d) Less than 7
238. Calculation of ATP gain for every glucose is made on certain assumptions. Choose the correct option in
     accordance with the statement given above
     a) The pathway functioning is sequential and orderly
     b) One substrate forms the reactant for the others

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c) TCA cycle and ETS pathway follow one after another
d) All of the above

239. Sucrose is converted into
     a) Glucose and fructose b) Triose phosphate and pyruvic acid
     c) Oxlic acid and citric acid d) Citric acid and pyruvic acid
240. Which of the following respiratory substrates requires the highest number of oxygen molecules for its
     complete oxidation?
     a) Tripalmitin b) Triolein c) Tartaric acid d) Oleic acid
241. The metabolic pathway through which the electron passes from one carrier to another is called
     a) Electron transport system b) Electron procedure system
     c) Electron moving procedure d) None of the above
242. In which one of the following options, the two names refer to one and the same thing?
     a) Citric acid cycle and Calvin cycle b) Tricarboxylic acid cycle and urea cycle
     c) Krebs’ cycle and Calvin cycle d) Tricarboxylic acid cycle and citric acid cycle
243. The complete combustion of glucose in respiration is represented by
     a) C6H12O6+6O2→6CO2+6H2O+ Energy
     b) C6H12O6+6CO2→+6O2+6H2O+ Energy
     c) C6H12O6+6O2+6CO2→+6CO2+6H2O+ Energy
     d) C6H12O6+6O2→6CO2+ATP→6CO2+6H2O+6O2 + Energy
244. The overall goal of glycolysis, Krebs’ cycle and the electron transport system is the formation of
     a) ATP in small stepwise units b) ATP in one large oxidation reaction
     c) Sugars d) Nucleic acids
245. In glycolysis, NADH + H+ is formed from NAD, when
     a) 3-phosphoglyceral dehyde (PGAL) is converted to 1, 3-bisphosphoglycerate (BPGA)
     b) Triose phosphate is converted to 2-phosphoglycerate
     c) 2-phosphoglycerate is converted to 2-phosphopyruvate
     d) 2-phosphopyruvate is converted to 2-pyruvic acid

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NEET BIOLOGY
RESPIRATION IN PLANTS

: ANSWER KEY :
1) c 2) b 3) a 4) a
5) c 6) c 7) c 8) c
9) b 10) d 11) b 12) a
13) c 14) a 15) a 16) b
17) b 18) c 19) d 20) b
21) d 22) c 23) b 24) b
25) b 26) c 27) a 28) a
29) b 30) c 31) d 32) a
33) a 34) a 35) b 36) a
37) c 38) d 39) b 40) c
41) b 42) a 43) d 44) a
45) c 46) b 47) c 48) b
49) a 50) b 51) c 52) d
53) d 54) d 55) c 56) d
57) d 58) c 59) a 60) a
61) a 62) c 63) c 64) a
65) c 66) a 67) b 68) a
69) b 70) a 71) d 72) d
73) c 74) b 75) b 76) c
77) c 78) c 79) c 80) a
81) c 82) d 83) b 84) a
85) a 86) b 87) a 88) a
89) d 90) c 91) a 92) d
93) b 94) d 95) c 96) a
97) b 98) d 99) c 100) c
101) c 102) d 103) a 104) a
105) b 106) b 107) c 108) a
109) c 110) a 111) c 112) d
113) b 114) c 115) c 116) a
117) b 118) a 119) a 120) b
121) a 122) b 123) a 124) b
125) d 126) a 127) d 128) a
129) d 130) b 131) a 132) a
133) b 134) d 135) c 136) d
137) a 138) d 139) a 140) b
141) c 142) c 143) a 144) b
145) a 146) a 147) b 148) b
149) d 150) d 151) c 152) a
153) a 154) b 155) a 156) d
157) b 158) d 159) a 160) d
161) a 162) a 163) a 164) c
165) d 166) a 167) a 168) a
169) a 170) c 171) b 172) a
173) b 174) c 175) a 176) b
177) d 178) a 179) d 180) a
181) b 182) b 183) a 184) c
185) b 186) d 187) c 188) b
189) a 190) b 191) c 192) b
193) c 194) c 195) b 196) a
197) b 198) d 199) d 200) d
201) c 202) b 203) a 204) b
205) c 206) b 207) a 208) d
209) c 210) a 211) a 212) a
213) d 214) a 215) d 216) d
217) b 218) a 219) d 220) a
221) c 222) c 223) a 224) b
225) c 226) d 227) c 228) c
229) a 230) d 231) b 232) c
233) b 234) b 235) b 236) d
237) d 238) d 239) a 240) b
241) a 242) d 243) a 244) a
245) a

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NEET BIOLOGY
RESPIRATION IN PLANTS

: HINTS AND SOLUTIONS :
1 (c)
Complex I of electron transport system (ETS) is
NADH dehydrogenase, which oxidase NADH
produced in the mitochondrial matrix during
citric acid cycle. Complex IV of cytochrome-and a3
and two copper centres.
2 (b)
In fermentation, incomplete oxidation of glucose
is achieved under anaerobic condition by sets of
reactions where pyruvic acid is converted to CO2
ethanol and sometimes lactic acid
3 (a)
The cellular respiration first takes place in the
cytoplasm.
4 (a)
The scheme of glycolysis was given by Gustav
Embden, Otto Mayerhof and J Parnas. It is the only
process in respiration for anaerobic organism. It
is ofter referred as the EMP pathway
5 (c)
Glycolysis was discovered by Gustav Embden,
Otto Mayerhof and J Parnas. To give honour to
them the glycolysis pathway is also called EMP
pathway by taking initial name of theirs
6 (c)
Mitochondria contains various enzymes as
follows:
1.Outer Membrane: Acetyl transferase,
glycerophosphatase, phospholipase-A,
monoamine oxidase, etc.
2.Inner Membrane: Cytochrome oxidase,
dehydrogenase, succinate, NADH dehydrogenase,
ATPase, etc.
3.Perimitochondrial Space: Adenylate kinase,
nucleoside diphosphokinase, etc.
4.Matrix : Pyruvate dehydrogenase, citrate
synthase, Aconitase, isocitrate dehydrogenase,
fumerase, 𝛼-ketogulatrate dehydrogenase, malate
dehydrogenase, etc.
7 (c)
In eukaryotes, all the reactions of tricarboxylic
acid (TCA) cycle or Krebs’ cycle takes place in the
matrix of mitochondria because all enzymes of
this cycle are found in the matrix of mitochondria
except Succinic dehydrogenase, which is located
in the inner membrane of mitochondria.
In prokaryotes, Krebs’ cycle occurs in cytoplasm.
8 (c)
Glyceraldehyde-3-phosphate is required for the
oxidative reaction during glycolysis.
9 (b)
Aerobic respiration occurs in the presence of
oxygen that leads to a complete oxidation of
organic substances and releases CO2, water and a
large amount of energy. This type of respiration is
most common in higher organism
10 (d)
On administration of glucose orally respiration
will take place.
11 (b)
30 ATP molecules could be generated from 686
kcal energy.
12 (a)
NADPH is formed during light reaction of
photosynthesis and also formed during hexose
monophosphate shunt (HMP shunt) of glucose
oxidation.
13 (c)
Plants can get along without respiratory organ
because plant part takes care of its own gas
exchange needs and less demand for gas
exchange. Because only during photosynthesis are
large volumes of gases exchanges and each leaf is
well adapted to take care of its own needs, during
these period
15 (a)

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During the oxidation process (occurs in inner
mitochondrial membrane during electron
transport system) enormous amount of free
energy is released, some of which is utilized by
inner membrane sub units of
F1 particles containing three coupling factors and
ATPase enzyme, in the synthesis of ATP
molecules.
16 (b)
Pyruvate which is formed by the glycolytic
catabolism of carbohydrate undergoes oxidative
decarboxylation by a complex set of reactions
catalysed by pyruvate dehydrogenase
17 (b)
The intermediate compound which link glycolsis
with Krebs’ cycle is acetyl Co-A.
18 (c)
All the enzymes of Krebs’ cycle, fatty acid
synthesis and amino acid synthesis are found in
matrix but Succinic dehydrogenase and
cytochrome oxidase are present on inner
membrane of mitochondria.
19 (d)
Enolase works on 2-phosphoglyceric acid (3C
compound), Aconitase on citric acid (6C
compound). Fumerase on Fumaric acid (4C
compound) and alcohol dehydrogenase on
acetaldehyde (2C-compound). Thus, increasing
order of these enzymes based on the carbon
number of the substrates on which they act is – IV,
I, III, II.
20 (b)
Pyruvic acid synthesized in glycolysis must enter
inside the mitochondnia, where oxidative
Decarboxylation occurs in presence of NAD+,
pyruvic acid Dehydrogenase complex and
coenzyme-A.
Pyruvic acid + NAD+ + Co-A +Co−A
→ Acetyl Co-A

• CO2+ NADH
  21 (d)
  Saccharomyces cerevisiae is a species of budding
  yeast. It is commonly known as ‘baker’s yeast’ or
  ‘brewer’s yeast’. The yeast ferments sugars
  present in the flour or added to the dough, giving
  off carbon dioxide (CO2) and alcohol (ethanol).
  The carbon dioxide is trapped as tiny bubbles in
  the dough, which rises.
  22 (c)
  Respiration and respiratory quotient is measured
  by respirometer
  23 (b)
  In Krebs’ cycle, acetyl Co-A adds its two-carbon
  fragment to oxaloacetate, a four-carbon
  compound. The unstable bond of acetyl Co-A is
  broken as oxaloacetate the coenzyme and
  attaches to the acetyl group. The product is the
  6C-citrate.
  24 (b)
  NADH is oxidised to NAD+ slowly in fermentation,
  through the reaction is very vigorous in case of
  aerobic respiration
  25 (b)
  Electron transport chain takes place in the inner
  mitochondrial membrane and consists of flavins,
  ubiquinone, cytochromes and oxygen as electron
  carriers.
  Sequence of electron transport :
  NADH2 → FAD → Co-Q →
  Cytochrome -b → Cyt-c1 → Cyt-a → Cyt –a3→
  O2
  26 (c)
  During exercise where O2 is inadequate for
  cellular respiration, pyruvic acid is reduced into
  lactic acid by lactate dehydrogenase
  27 (a)
  Fermentation accounts for only a partial
  breakdown of glucose whereas in aerobic
  respiration it is completely degraded to CO2 and
  H2O
  28 (a)
  N and P are required by plants for ATP formation.
  30 (c)
  Pyruvic acid, generated in the cytosol is
  transported to mitochondria and thus initiate the
  second phase of respiration. Before pyruvic acid
  enters Kreb’s cycle, operative in the mitochondria,
  one of the three carbon atoms of pyruvic acid is
  oxidised to carbon dioxide in a reaction called
  oxidative decarboxylation
  31 (d)
  Usually carbohydrate are oxidised to release
  energy, but proteins, fats and even organic acids
  can be used as respiratory substances in some
  plants, under certain condition
  32 (a)
  One of the three carbon atoms of pyruvic acid is
  oxidised to carbon dioxide. The combination of
  the remaining two carbon acetate unit is readily
  accepted by a sulphur containing compound
  coenzyme A (Co-A) to form acetyl Co-A. This is the

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connecting link between glycolysis and Kreb’s
cycle
33 (a)
In eukaryotes, electron transport and oxidative
phosphorylation occur in the inner membrane of
mitochondria. The significant enzymes of inner
mitochondrial membrane are enzymes of
electron transport pathways viz. NAD, FAD, DPN
(diphosphopyridine nucleotide) dehydrogenase,
five cytochromes (cytochrome-b, cytochrome-c,
cytochrome-𝑐1, cytochromes-a and cytochrome
�
�3), ubiquinone or coenzyme-Q10, non-haem
copper and iron, ATP synthetase, succinate fatty
acid acyl transferase.
34 (a)
Saprophytes like fungi are dependent on dead and
decaying matter
35 (b)
Mitochondria are known as power house of cell.
Glyceraldehyde-3-phosphate dehydrogenation
reaction is found in cytoplasm during glycolysis,
other three reactions take place in mitochondria.
36 (a)
In the process of glycolysis, 6 carbon molecules of
glucose is split into 2, 3-carbon molecules of
pyruvic acid. In this, one molecules of NAD+ are
reduced for each glucose molecule. The energy
stored with the NADH is released in the electron
transport chain. This process (glycolysis) occurs
in cytosol
37 (c)
The oxidation of Succinic acid to Fumaric acid in
Krebs’ cycle is catalyzed by Succinic
dehydrogenase. Succinic dehydrogenase is attach
to mitochondrial inner membrane.
38 (d)
Succinate dehydrogenase enzyme is present on
inner membrane of mitochondria and catalysed
the oxidation of succinate to fumarate.
39 (b)
The TCA cycle starts with the condensation of
acetyl group with oxaloacetic acid (OAA) and
water to yield citric acid. The reaction is catalyzed
by the enzyme citrate synthase and molecule of
Co-A is released
40 (c)
Krebs’ cycle is also called as citric acid cycle
because citric acid is the first product of this cycle
and also called Tricarboxylic acid cycle (TCA)
because citric acid is a called Tricarboxylic acid.
In eukaryotic organisms, all reactions of Krebs’
cycle take place in matrix of mitochondria
because all enzymes of this cycle are found in
matrix of mitochondria except Succinic
dehydrogenase (located in inner membrane of
mitochondria).
41 (b)
In electron transport chain, cytochrome-a is an
electron carrier, which contains copper with iron.
It picks up electrons to oxygen. Therefore, oxygen
accepts the terminal electrons.
42 (a)
In electron transport system oxygen acts as the
final hydrogen acceptor where it derives the
whole process by removing hydrogen from the
system
43 (d)
If a starving plant is provided with glucose, its
rate of respiration will increase because of the
availability of food for respiration.
44 (a)
Malic acid is a product of aerobic respiration.
Ethyl alcohol and lactic acid are formed as a result
of anaerobic respiration (fermentation), while
pyruvic acid is produced during both-aerobic and
anaerobic respiration.
45 (c)
A – 2H+, B – F0, C – F1
46 (b)
In Krebs’ cycle, pyruvic acid is converted into
carbon dioxide and water.
47 (c)
An enzyme may have areas that control the
confirmation of active sites. They are called
Allosteric sites. Such an enzyme is called
Allosteric enzyme, e.g., glucokinase,
phosphofructokinase. Substance, which bring
about changes in Allosteric sites are called
modulators.
48 (b)
In glycolytic pathway, 3PGAL is converted into 1,
3-diphosphoglyceric acid by an oxidation and
phosphorylation reaction, which occurs in
presence of H3PO4 and coenzyme NAD.
3-phosphoglyceraldehyde + NAD+ + Pi−2 → 3
phosphoglyceraldehyde dehydrogenase 1, 3
diphosphplyceric acid + NADH +H+
49 (a)
Pyruvic acid forms as a result of glycolysis in
cytoplasm of cell. Oxidation of pyruvic acid into

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acetyl Co-A begins the citric acid cycle (Krebs’
cycle) in mitochondria.
50 (b)
When oxygen is not available, yeast or some other
microbes respire anaerobically. In case of
anaerobic respiration, the value of respiratory
quotient is not utilized, eg,
C6H12O6 Zymase → 3C2H5OH + 2CO2 +
Energy
Glucose Ethyl alcohol
51 (c)
All living organisms need energy for carrying out
daily life activities and is obtained by oxidation of
macromolecules
52 (d)
In TCA cycle TCA substrate oxidise by releasing
NADH + H+, which produces three ATP
molecules. So, one glucose molecule through TCA
produces 6 NADH + H+. So 18 ATP produced
through electron transport chain. 2 FADH2 of
Kreb’s cycle produced 4 ATP
53 (d)
Chemiosmotic hypothesis of ATP synthesis was
proposed by Peter Mitchell in 1961.
54 (d)
Alcoholic fermentation by yeast causes
decorboxylation of pyruvate to acetaldehyde
producing CO2 as byproduct. Acetalatehyde
accepts 2H atoms from NADH2 to produce
ethanol
55 (c)
Pyruvic acid is intermediate compound, which is
produced during oxidation of all types of
respiratory substrates carbohydrates, fats and
proteins

Option (d) Acetyl Co-A may also be answer but
more appropriate is pyruvic acid as it formed
directly by all these respiratory substrates
56 (d)
Respiratory quotient (RQ) is the ratio of the
volume of carbon dioxide produced to the volume
of oxygen consumed in respiration over a period
of time. The values of RQ for various substrates
are :
Carbohydrate – One
Fat, protein – Less than one
Organic acid – More than one
Succulents – Zero
57 (d)
Pyruvic acid inters in the matrix of mitochondria
and undergoes acetylation by oxidative
Decarboxylation to form 2-carbon compound
acetyl Co-A. Krebs’ cycle is basically a catabolic
cycle as it oxidises acetyl Co-A and organic acids
into carbon dioxide and water.
58 (c)
Out of the four phases of cellular respiration all
except glycolysis (occur in cytoplasm-outside
mitochondria) take place in mitochondria. The
enzymes of Krebs’ cycle are located in the matrix
of mitochondria, while that of oxidative
phosphorylation are located in inner
mitochondrial membrane.
59 (a)
ATP is an energy rich compound, which is
structurally most similar to a molecule of RNA
nucleotide.
60 (a)
DCMU is a herbicide which acts as an inhibitor of
non-cyclic electron transport; PMA is fungicide
which reduces transpiration; colchicine is an
antimicrobial drug, it causes prevention of mitotic
spindle formation thus blocking the mitosis
61 (a)
Oxidation of one molecule of NADH gives rise to 3
molecules of ATP.
62 (c)
An amphibolic pathway is a biochemical pathway
that serves both anabolic and catabolic processes.
An important example of an amphibolic pathway
is the Krebs’ cycle, which involves both the
catabolism of carbohydrates and fatty acid and
the synthesis of anabolic precursors for amino
acid synthesis, eg, 𝛼-ketogluturate and
oxaloacetate.
63 (c)
In alcoholic fermentation,
1.NADH (formed during conversion of triose
3phosphate to 3-phosphoglycerate) is oxidized to
NAD+
2.Electrons are accepted by acetaldehyde formed
by Decarboxylation of pyruvate.
64 (a)

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Wherever oxygen involves as a substrate is
known as oxidation. Therefore respiration is
oxidation process
65 (c)
Net gain of ATP during aerobic respiration
1.Glycolysis provides 2ATP molecules and
2NADH+H+
2.Pyruvate oxidation yields 2NADH + H+
3.Krebs’ cycle produces 2GTP molecules, 6NADH

• H+ and 2FADH2 molecules.
  4.In electron transport system one NADH + H+
  produce 3ATP and FADH2 produces 32 or 34 ATP.
  2ATP from glycolysis + 2GTP from
  TCA cycle and 32/34 ATP from
  ETS/ETC =38/36 ATP molecule.

66 (a)
Cyanides, antimycin A, carbon monoxide inhibits
the process of electron transport chain
68 (a)
There is two step in glycolysis where ATP is
formed or synthesised by ADP
(i) When 1, 3, bisphosphoglyceric acid is changed
into 3-phosphoglyceric acid
(ii) When phosphoenolpyruvate (PEPA) is
changed into pyruvic acid
69 (b)
Fats give maximum energy on oxidation. As
palmitic acid is a fatty acid produced by
hydrolysis of fat, hence, produces maximum
number of ATP on oxidation.
70 (a)
Glycolysis is a series of reactions that takes place
in the cytoplasm of all prokaryotes and
eukaryotes. The role of glycolysis is to produce
energy (both directly and by supplying substrate
for the citric acid cycle and oxidative
phosphorylation) and to produce intermediates
for biosynthetic pathway.
71 (d)
Krebs’ cycle begins with the reaction of acetyl Co
A with oxaloacetic acid in presence of the enzyme
citrate synthase.
72 (d)
Acetyl Co-A is the link between glycolysis and
Kreb cycle, for formation of acetyl Co-A the Co
factor TPP, lipoic acid and Mg2+, Co-A is required
73 (c)
Carbon dioxide is released by anaerobic
repiration in plants

75 (b)
TCA cycle starts with the condensation of acetyl
group with Oxalo Acetic Acid (OAA) and water to
yield citric acid. The reaction is catalysed by the
enzyme citrate synthase
76 (c)
Respiratory quotient (the ratio between the
volume of carbon dioxide liberated to the volume
of oxygen absorbed in respiration) is less than
one, when fats and proteins are respired. Castor
oil is rich in fatty substances.
77 (c)
Before entering respiratory pathway amino acids
are deaminated
78 (c)
34 molecules of ATP (30 through NADH and 4
through FADH2) are obtained as a result of
oxidative phosphorylation. Rest 4 molecules are
obtained as a result of direct phosphorylation.
79 (c)

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Decarboxylation occurs in Krebs’ cycle.
80 (a)
The citric acid cycle for production of energy in
the cell was described by Kreb’s, therefore TCA
cycle is also known as Kreb’s cycle
81 (c)
1 molecule of glucoses yields 262 8 kcal of usable
energy
No. of glucose molecule required to produce
4800 kcal energy =4800
262.8
=18
1 molecule of ATP yield 7.3 kcal of usable energy
No. of ATP molecules required to produce
4800 kcal energy =4800
7.3
=657
82 (d)
Coliforms are defined as aerobic or facultative
anaerobic, Gram negative, non-endospore
forming, rod-shaped bacteria that ferment lactose
to form gas.
83 (b)
Due to excessive contraction of muscles (eg, leg
muscles in hurdle race), the metabolic products of
glycolysis accumulate in them which leads to
muscle fatigue. Normally, pain is experienced in
the fatigued muscle.
84 (a)
Like the bacterial respiration, in animal cells
during the exercise when oxygen is inadequate for
cellular respiration pyruvic acid is reduced to
lactic acid by lactate dehydrogenase. The reducing
agent is NADH+H+ which is reoxidised to NAD+
in both the process
85 (a)
During the respiration, compounds are needed to
break and perform the next step to release ATP. It
is specifically called respiratory substrate
86 (b)
The given compound (C51H98O6) is tripalmitin (2
molecules) used as a substrate. This substrate is
used in respiration the respiratory quotient is less
than 1. The given below derivation explained
much clear way
Respiratory quotient =Evolved CO2
Consumed O2
=102 CO2
145 O2
=
0.7
87 (a)
All the energy required for life processes is
obtained by oxidation of some macromolecules
that we call food.
Only green plants and cyanobacteria can prepare
their own food by the process of photosynthesis.
They trap light energy and convert it into
chemical energy that is stored in the bond of
carbohydrates like glucose, sucrose and starch
88 (a)
Intermediate in the pathway are utilised to
synthesise other compound
89 (d)
In plants, glucose is derived from sucrose which is
the end product of photosynthesis or form
storage carbohydrate
90 (c)
As per chemiosmotic hypothesis ATP synthetase
becomes active in ATP formation only where
there is a proton gradient having higher
concentration of H+ or protons on the inner side
as composed to outer side.
91 (a)
Louis Pasteur observed that yeast cells grew
rapidly in air but used little sugar and produced
little carbon dioxide and ethanol. Under anaerobic
conditions, they grew slower but used more sugar
and produced more carbon dioxide and ethanol.
This phenomenon of inhibition of breakdown of
carbohydrate and production of ethanol is known
as Pasteur effect. Biochemically, Pasteur effect is
an Allosteric inhibition of phosphofructokinase
enzyme in the presence of oxygen.
92 (d)
Organic acid evolves more carbon dioxide than
volume of oxygen consumed when broken down
as respiratory substrate under aerobic conditions,
i.e., RQ is more than unity.
93 (b)
Anaerobic respiration in microorganisms is called
fermentation. It takes place in absence of oxygen
and produced lactic acid, ethyl alcohol, etc, from
glucose. It is useful in manufacture of wine, beer
and bread.
94 (d)
The main purpose of cellular respiration is to get
energy that is utilised for functioning various
purpose. Glucose energy is converted into ATP,
which is utilised by cell
95 (c)
Glucose-6-phosphate yields less than 4 kcal/mol,
when its phosphate bond is hydrolysed.
96 (a)
5g moles glucose on complete oxidation releases
3430 kcal of energy.
97 (b)

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NADP, NAD and FAD are coenzyme formed from
vitamins and work as electron acceptor in cellular
metabolism.
98 (d)
Glycolysis of one molecule of glucose produces
2PGAL, thus of three molecules will produce
6PGAL.
Respiration of one molecule of glucose or 2PGAL
produces 38ATP molecules, thus, of 6PGAL will
produce 114 ATP molecules. Out of the given
option, 120 ATP is the nearest correct answer.
99 (c)
Aspartic acid + 𝛼-ketoglutaric acid ⟶oxaloacetic
acid + glutamic acid
This is an example of transamination reaction. In
this, amino group of aspartic acid is transferred to
glutamic acid.
100 (c)
Acetyl Co-A is a common intermediate of
carbohydrate and fat metabolism. It is a substrate
entrant of Krebs’ cycle and acts as a connecting
link between glycolysis and Krebs’ cycle.
101 (c)
The pyruvic acid formed during glycolysis enters
to mitochondria where oxidative Decarboxylation
takes place and acetyl Co-A is formed. It occurs in
presence of NAD+, pyruvic acid Dehydrogenase
complex and coenzyme-A. pyruvic acid + NAD+ →
Acetyl Co-A + NADH + H+ + CO2
103 (a)
Oxidation of one molecule of NADH give rise to 3
molecules of ATP while that of one molecule of
FADH2 produces 2 molecules of ATP
104 (a)
Respiration is defined as breaking down of C-C
bond of various organic molecules by oxidation
process for cellular use
105 (b)
If oxygen is not available, pyruvic acid undergoes
anaerobic respiration/fermentation, but under
aerobic condition, the pyruvic acid enters into
mitochondria and converted to Acetyl Co-A. Acetyl
Co-A functions as substrate entrant for Krebs’
cycle so, a connecting link between glycolysis and
Krebs’ cycle.
Glycolysis is the process of breakdown of glucose
(hexose sugar) to two molecules of pyruvic acid
through a series of enzyme mediated reactions. It
occurs in cytoplasm and is common both to
aerobic and anaerobic respiration. Last product is
pyruvic acid.
106 (b)
The electron acceptors of respiratory chains occur
in linear sequences (cyt.-b, c, a, a3) and their
enzymes are components of the inner
mitochondrial membrane.
107 (c)
In microorganisms, the term anaerobic
respiration is replaced by fermentation. The
pyruvic acid formed in glycolysis is transformed
to ethyl alcohol and release 2 ATP molecules.
108 (a)
One of the three carbon atoms of pyruvic acid
which is the end product of glycolysis is oxidised
to carbon dioxide in a reaction called oxidative
decarboxylation. Pyruvate is first decarboxylated
and oxidised by the enzyme pyruvate
dehydrogenase
109 (c)
Saccharomyces shows Pasteur’s effect.
110 (a)
Fermentation is a type of cellular respiration
found in plants and some unicellular
microorganism, which does not require oxygen,
i.e., anaerobic respiration, and that results in the
production of ethanol from glucose and release of
small amount of energy.
111 (c)
Krebs’ cycle is also called as citric acid cycle. Citric
acid (Tricarboxylic acid) is the first product of
this cycle.
112 (d)
Six carbon dioxide molecules are released by
complete oxidation of one glucose molecules. Two
carbon dioxide molecules are released during
oxidative Decarboxylation reaction and four
carbon dioxide molecules are released in Krebs’
cycle or tricarboxylic Acid cycle.
113 (b)
The respiratory decomposition of fatty acids is
known as beta oxidation, which occurs in liver
and adipose tissue. First of all, there is activation
of fatty acid, then dehydrogenation of activated
fatty acid takes place. This is followed by
hydration. The 𝛽-hydroxyl acyl derivative is
converted to 𝛽-keto derivative which then reacts
with Co-A.
114 (c)

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Respiratory Quotient (RQ) is the ratio of volume
of CO2 released to the volume of O2 absorbed
during respiration. In case of organic acids (eg.,
oxalic acid), more CO2 is released than the O2
absorbed. Hence, RQ of organic acids is always
more than one.
2(COOH)2 + O2 → 4CO2 + 2H2O + Energy

RQ = 4𝐶O2
1O2
= 4
115 (c)
ATP is called as energy currency of cell.
116 (a)
Breakdown processes within the living organism
is also called catabolism
117 (b)
In fermentation, the incomplete oxidation of
glucose is achieved under, anaerobic condition by
set of reactions, where pyruvic acid is converted
into carbon dioxide and ethanol. The enzyme,
pyruvic acid decarboxylase and alcohol
Dehydrogenase catalyse these reactions.
118 (a)
ATP is utilised at two steps – First in the
conversion of glucose into glucose – 6 phosphate
and second in the conversion of fructose – 6 –
phosphate to fructose 1, 6 biphosphate
119 (a)
Aerobic respiration takes place within the
mitochondria, the final product of glycolysis,
pyruvate is transported from the cytoplasm into
the mitochondria
121 (a)
Oxaloacetic acid – 4C. Phosphoglyceric acid – 3C
Ribulose bisphosphite – 3C. Phosphoenl pyruvate – 3C
122 (b)
In the non-competitive inhibition of enzymes, the
inhibitor (cyanide) has no structural similarity
with the substrate (cytochrome-c) and binds to
the enzyme at a point other than its active site
which leads to change in globular structure of
enzyme. Hence, even if the substrate is able to
bind with the enzyme, catalysis will not take
place.
123 (a)
During anaerobic respiration, one molecule of
glucose gives two molecules of ATP. Thus, 8
molecules of ATP are produced.
124 (b)
Peter Mitchell (1961) proposed the chemiosmotic
mechanism of ATP synthesis which, states that
ATP synthesis occurs due to H+ flow through a
membrane. It includes development of proton
gradient and proton flow.
125 (d)
In the process of glycolysis, 6-carbon molecules of
glucose are split into two 3-carbon molecules of
pyruvic acid. In this, two molecules of NAD+ are
reduced for each glucose molecule. The energy
stored within the NADH is released in the electron
transport chain.
126 (a)
Citric acid cycle is also known as Tricarboxylic
acid cycle (TCA)
127 (d)
In respiration, whether it is aerobic or anaerobic
glucose undergoes oxidation to form energy. In
plants glucose is derived from sucrose which is
the end product of photosynthesis or from
storage carbohydrate. Sucrose is converted into
glucose and fructose by the enzyme invertase to
enter into the first step of respiration which is
glycolytic pathway
128 (a)
Fat breakdown into fatty acid and glycerol before
entering into the respiratory pathway
129 (d)
In glycolysis, water molecule is removed during
conversion of 2-phosphoglycerate to phosphoenol
pyruvate.
Conversion of fructose-6-phosphate to fructose 1
6 biphosphate is characterized by
phosphorylation.
130 (b)
Pentose Phosphate Pathway (or Warburg
Lippman Dickens cycle) is an alternate method of
aerobic respiration, which occurs in the
cytoplasm of mature cell. This pathway accounts
for 60% of total respiration in liver cells. In this,
for every six molecules of glucose, one molecule is
completely oxidized in CO2 and reduced
coenzymes, while 5 are regenerated.
131 (a)
In the first reaction of citric acid cycle one
molecule of acetyl Co-A combines with 4-carbon
Oxalo Acetic Acid (OAA) to form 6 carbon citric
acid and Co-A is released
132 (a)

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During fermentation, the pyruvic acid releases
one molecule of CO2 to produce acetaldehyde. The
acetaldehyde, then reoxidises NADH and is itself
reduced to ethanol. These reactions are catalysed
by the enzyme, pyruvic acid decarboxylase and
alcohol dehydrogenase

133 (b)
In the Krebs’ cycle, when Succinic acid undergoes
oxidation or dehydrogenation to form Fumaric
acid, two hydrogens are transferred to FAD. FAD
is reduced to FADH and enzyme involved in this
step is Succinic acid dehydrogenase.
134 (d)
Respiratory pathway involved in both anabolism
and catabolism, hence it is regarded as amphibolic
pathway. In respiratory pathway not only the
glucose but also amino acid and fatty acid can be
used as intermediatory substances
135 (c)
The RQ value of 4 may be expected from complete
oxidation of oxalic acid.
136 (d)
Fatty acid, protein and earbohydrak would be
broken down to acetyl Co-A before entering the
respiratory pathway when it is used as a
substrate
137 (a)
Anaerobic arespiration occurs without O2 which
convince that it happens in lower organism
138 (d)
During the step of Krebs’ cycle, where Succinic
acid undergoes oxidation or dehydrogenation to
form Fumaric acid, FAD is reduced to FADH2 and
enzyme involved in this step is Succinic acid
dehydrogenase.
Conversion of isocitric acid to 𝛼-ketoglutaric acid,
malic acid to oxaloacetic acid and pyruvic acid to
acetyl Co-A, all involve reduction of NAD to
NADH+H+
139 (a)
One molecule of pyruvic acid converted in acetyl
Co-A for 3 molecule of NADH+H+
140 (b)
In 1950, Kolliker for the first time seen
mitochondria. Later on C Benda coined the term
mitochondria. These are the sites of cellular
respiration, oxidative phosphorylation, synthesis
of haeme protein, cytochrome, myoglobin, etc.
141 (c)
The energy released by oxidation in respiration is
not directly used but it stored as ATP. Which is
broken down whenever energy needs to be
utilised
142 (c)
RQ is one in case of carbohydrates, while for fatty
acids is less than one and for organic acids RQ is
more than one.
143 (a)
Sucrose or cane sugar is widely distributed among
higher plants. Its commercial sources are solely
sugarcane and beet. It is used as substrate for the
formation of alcohol.
144 (b)
The correct sequence in glycolysis is
Glucose-6-phosphate → 3-phosphoglyceraldehyde
Phosphoenol ←3-phosphoglyceric acid↲
Pyruvate
↓
Pyruvic acid.
145 (a)
Cyanide is a deadly poison of respiration and
inhibit the activity of cytochrome-c oxidase
complex (which contains cytochrome-a and
cytochrome-a3) of electron transport chain of
aerobic respiration. Thus, no proton gradient will
be established and no ATP will be formed. Along
with as the reduction of NADH and FADH2 is also
ceased due to blockage of ETS, the availability of
hydrogen acceptors like NAD+ and FAD is ceased
for Krebs’ cycle and glycolysis. Cyanide resistance
pathway is anaerobic respiration.
146 (a)
Hexokinase causes phosphorylation of glucose to
glucose-6 phosphate in both glycolysis and
pentose phosphate pathway. Both glycolysis and
phosphate pathway occur in cytoplasm. Glucose +
ATP Hexokinase → Glucose 6-phosphate + ADP
147 (b)
The aerobic respiration takes place within the
mitochondria, the final product of glycolysis
pyruvate is transported from the cytoplasm into
the mitochondria. The major events in aerobic
respiration are

Page| 28

The complete oxidation of pyruvate by the
stepwise removal of all the hydrogen atoms,
leaving 3 molecules of CO2.
The passing on of the electrons removed as part
of the hydrogen atoms to molecular O2 with
simultaneous synthesis of ATP
148 (b)
Glycolysis is an essential and first path of
respiration. It is common in both aerobic and
anaerobic respiration and occurs in the cytosol of
all living cells of prokaryotes as well as
eukaryotes
149 (d)
Oxidative phosphorylation or ATP synthesis from
NADH occur only under aerobic condition.
151 (c)
The activity of succinate dehydrogenase is
inhibited by Malonate.
152 (a)
Citric acid is produced by the fermentation of
sugar by Aspergillus niger, Mucor sp and yeast.
153 (a)
In the process of respiration the compound, i.e.,
glucose reacts with oxygen which is called
oxidation therefore organic substance gets
oxidised
154 (b)
Pyruvate is broken down to CO2 and H2O in citric
acid of tricarboxylic acid cycle (TCA)
155 (a)
Preparatory phase before fermentation is called
upstream processing while downstream
processing is the name given to the stage after
fermentation, when the desired product is
recovered and purified.
156 (d)
Retting is facilitated by anaerobic butyric acid
bacteria such as Clostridium botulinum,
Clostridium tetani and Clostridium perfringens.
157 (b)
RQ is the ration of the volume of carbon dioxide
released to the volume of oxygen taken in
respiration. It depends on the nature of the
substrate, which is oxidised. For carbohydrates
RQ is one, for fats and proteins less than one but
more than one for organic acids, etc.
158 (d)
The complex V of ETS of mitochondrial membrane
is ATP synthase, which has a head piece, stalk and
a base piece. Out of these, the head piece is
identified as the coupling factor 1(F1), stalk
portion is necessary for binding 𝑖 to inner
mitochondrial membrane and base piece is
isolated as F0 and present within the inner
mitochondrial membrane.
159 (a)
Protein breaks down into amino acid then enter
into the glycolytic pathway
160 (d)
Ethyl alcohol is commercially manufactured from
sugarcane. Molasses is the byproduct of sugar
industry. Ethanol is produced by the fermentation
of molasses (contains glucose and fructose) by
using yeast, Saccharomyces cerevisiae.
161 (a)
Krebs’ cycle takes place in matrix of mitochondria.
Largest amount of phosphate bond energy is
produced in Krebs’ cycle due to oxidation by O2.
We get 6CO2, 8NADH2, 2FADH2 and 2ATP
molecules in Krebs’ cycle.
162 (a)
In electron transport system, last electron
acceptor is oxygen
163 (a)
Glucose and fructose are both converted to
ethanol and carbon dioxide in presence of Zymase
enzyme.
C6H12O6
Zymase → 2𝐶2𝐻5OH + 2CO2
Glucose or Ethanol
Fructose
164 (c)
Glycolysis is the degradation of glucose molecule
with net gain of 2ATP molecules per glucose
molecule. It occurs both in aerobic and anaerobic
conditions.

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165 (d)
For fatty substances, RQ is generally less than one.
2C51H96O6 + 145O2 → 102C𝑂2 + 98H2O
RQ = 𝑐𝑜2
O2
= 102
145
= 0.7 (less than unity)

166 (a)
DCMU is a herbicide which acts as an inhibitor of
non-cyclic electron transport; PMA is fungicide
which reduces transpiration; colchicines is an
antimicrobial drug, it causes prevention of mitotic
spindle formation thus blocking the mitosis.
167 (a)
With the complete oxidation of pyruvate by the
stepwise removal of all the hydrogen atoms form
3 molecules of CO2, which occurs in matrix of the
mitochondria
168 (a)
In anaerobic respiration bacteria produce lactic
acid from pyruvic acid
169 (a)
Strains of Saccharomyces cerevisiae (yeast) are
extensively used for leavening of bread. During
fermentation, the yeasts produce alcohol and
carbon dioxide, which leave and the leavened
bread becomes porous.
170 (c)
Before entering respiratory pathway amino acids
are deaminated
171 (b)
Pyruvic acid is an intermediate compound
common for aerobic and anaerobic respiration
because it is the end product in glycolysis and
initial product in anaerobic respiration.
172 (a)
During alcoholic fermentation of glucose
molecule, pyruvic acid is first decarboxylated to
form acetaldehyde and CO2, which is then
changed to ethyl alcohol with help of NADH. Net
gain is 2ATP molecules per glucose molecule.
C6H12O6 +2ADP + 2Pi → 2C2H5OH
Glucose Ethyl alcohol
+ 2CO2 +2ATP +2H2O
173 (b)
4 ATP are formed in glycolysis but 2 ATP used
2 ATP in Krebs’ cycle
34 ATP from electron transport chain
40 ATP
174 (c)
It is a fact that the living cells are organised in thin
layers inside and beneath the bark. They also have
dead cells in the interior which provide
mechanical support
175 (a)
Sunlight is the ultimate source of energy on earth.
Green plants converted sunlight in form of
sucrose. Animals take food from plants and get
energy by oxidation of glucose.
176 (b)
Dough kept overnight in warm weather becomes
soft and spongy due to fermentation.
177 (d)
RQ is the ratio of volume of carbon dioxide
evolved and volume of oxygen consumed.
178 (a)
On oxidation of fats, maximum amount of energy
is liberated.
179 (d)
NADH2→NAD→NADH2
NADH2→FAD→FADH2
The former operates in liver heart and kidney
cells and no energy is spent, while the second
operates in muscle and nerve cells and lowers the
energy level of 2NADH2 by 2 ATP molecules
180 (a)
Krebs ’cycle involves 8 steps to oxidize 2
molecules of acetyl Co-A produced in transition
reaction completely into 4CO2, 10H2O, 2ATP,
2FADH2 and 6NADH+H+
181 (b)
Respiratory quotient = Evolved CO2
Consumed O2

Hence, how much O2 will consume. It all depends
substrate
182 (b)
In anaerobic respiration, i.e., absence of O2,
glycolysis and fermentation involves. In
fermentation incomplete oxidation of glucose is
processed by sets of reaction where pyruvic acid
is converted to CO2 and ethanol
183 (a)
It is well known fact that photosynthesis in
eukarytoes occurs in chloroplast whereas in
prokaryotes it is in cytoplasm
184 (c)
Anaerobic respiration occurs in absence of
oxygen. It is found in deep-seated tissues of plants
and animals, germinating seeds, yeasts and
bacteria. During anaerobic respiration of yeast,

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two ATP produced from each glucose molecule.
Hence, 38 ATP will produce from 19 glucose
molecules.
185 (b)
In aerobic respiration, glycolysis is linked with
Krebs’ cycle through acetyl Co-A because pyruvic
acid (end-product of glycolysis) first converted
into acetyl Co-A. The acetyl Co-A enters in the
Krebs’ cycle. The formation of acetyl Co-A is
involved with some cofactors like Mg ions,
thiamine pyrophosphate (Vitamin-B1), NAD+ , Co
A and lipoic acid.
186 (d)
In anaerobic respiration CO2 is evolved but
oxygen is not used. Therefore in such case
respiratory quotient will be infinite. 𝑒.𝑔.,
C6H12O6
Zymase → 2 C2H5OH+2 CO2+ Energy
Glucose
Where, respiratory quotient = Evolved CO2
Consumed O2

=2 CO2
0 O2
=∞(Infinity)
187 (c)
The NADH synthesised in glycolysis is transferred
into the mitochondria and undergoes oxidative
phosphorylation
188 (b)
Total gain of 38 ATP molecules during aerobic
respiration of one molecule of glucose
189 (a)
During glycolysis, in the presence of enzyme
Hexokinase, glucose is converted into glucose-6
phosphate by using one ATP molecule in presence
of Mg2+
190 (b)
In the presence of Zymase, alcoholic fermentation
takes place.
191 (c)
During the conversion of Succinyl Co-A to Succinic
acid, a molecule of GTP is synthesized. This is a
substrate level phosphorylation. In a coupled
reaction, GTP is converted to GDP with the
simultaneous synthesis of ATP from ADP.
192 (b)
Pyruvic acid is 3C-compound. One of the three
carbon atoms of pyruvic acid is oxidised to carbon
dioxide in a reaction called oxidative
decarboxylation. Pyruvate is first decarboxylated
and then oxidised by the enzyme pyruvate
dehydrogenase. The combination of the
remaining 2-carbon acetate unit is readily
accepted by a sulphur containing compound,
coenzyme A (Co-A) to form acetyl Co-A
194 (c)
Generally lower organism, 𝑒.𝑔., bacteria and fungi
performs anaerobic respiration but also occur in
higher organism
195 (b)
Pathway – A is glycolysis ⟶2 NADH+H−
Pathway – B is Kreb’s cycle ⟶6 NADH+H+
Pathway – C is Electron transport system
Between pathway A and pathway B ⟶2 NADH+
H+ produced
196 (a)
In electron transport chain respiratory process
are to release and utilise the energy stored in
NADH + H+ and FADH2. This is accomplished
when they are oxidised through the electron
transport system and the electron are passed on
to O2 resulting in the formation of H2O
197 (b)
During citric acid cycle, 3 molecules of NAD+ and
one molecule of FAD (Flavin Adenine
Dinucleotide) are reduced to produce NADH and
FADH2 respectively. These reduced electron
carriers pass on the hydrogen atoms to oxygen
through electron transport system, yielding II
more ATP molecules for each molecule of pyruvic
acid.
In addition one ATP molecules is generated
directly during the cycle to give a total of 12 ATP
molecule per pyruvic acid molecules. As two
molecules of pyruvic acid are produced from each
molecule of glucose a total of 24 molecules of ATP
are formed during the citric acid cycle
198 (d)
When the fats respire, the value of RQ is less than
one.
199 (d)
Glycolysis involves ten step for each step, specific
enzyme needs to go next step
200 (d)
ATP is a coenzyme. Coenzyme is an organic
cofactor molecule smaller than protein that bonds
with a specific enzyme, while the reaction is being
catalysed.
201 (c)
Oxidative phosphorylation refers to the synthesis
of ATP from ADP and inorganic phosphate by
chemiosmosis. It occurs with the help of energy

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obtained from oxidation of reduced enzymes
formed in cellular respiration.
202 (b)
Krebs’ cycle or citric acid cycle occurs in the
matrix of mitochondria. It occurs in aerobic
respiration. Acetyl Co-A is the connecting link
between glycolysis and Krebs’ cycle. Pyruvic acid
is oxidized into acetyl Co-A (6C), which is the first
or initiating organic acid of Krebs’ cycle.
203 (a)
Most cells of a plants have a part of their surface
in contact with air. This is also facilitated by the
loose packing of parenchyma cells in leaves
204 (b)
A variety of enzymes control different steps of
cellular respiration.
205 (c)
NAD+ and NADP+ accepts two electrons and one
proton to get reduced to NADH and NADPH
respectively
206 (b)
The product of glycolysis is pyruvic acid the
products of Krebs’ cycle are CO2 and water.
207 (a)
Chemiosmosis is the diffusion of ions across a
selectively permeable membrane. More
specifically, it relates to the generation of ATP by
the movement of hydrogen ions across a
membrane during cellular respiration.
ATP synthase is the enzyme that makes ATP by
chemiosmosis. The generation of ATP by
chemiosmosis occurs in chloroplasts and
mitochondria as well as in some bacteria.
208 (d)
Cytochromes are small proteins (intrinsic
membrane proteins) that contain a cofactor,
haem, which holds an iron atom. The iron carries
electrons and cycles between +2 and +3
oxidation states. These form a part of electron
transport chain in mitochondria and chloroplast
and act as an electron transporter or electron
acceptor in respiration and photosynthesis.
209 (c)
RQ is the ratio of volume of carbon dioxide
evolved and volume of oxygen consumed. If RQ is
less than one it means the oxidation of the
respiratory substrate consumed more oxygen
than the amount of carbon dioxide released.
Volume of carbon dioxide < Volume of oxygen
210 (a)
The flowchart given shows the step in glycolysis.
The glucose 6-phosphate breaks into fructose 6
phosphate and then fructose 1, 6-bisphosphate.
Fructose -1, 6 bisphosphate convert into 3
phophoglyceraldehydes and then 1, 3-
bisphosphoglyceric acid
211 (a)
Cyanide reacts with one of the proteins
(cytochrome-a3) in the electron transport system
and prevents transfer of electron to oxygen. It
leads to checking the ATP formation through
oxidative phosphorylation. ATP is required for
active transport of substances across the plasma
membrane, besides some other metabolic
reactions.
212 (a)
Brandy and whisky requires both distillation and
fermentation as fermentation inhibited at an
alcohol level of 10-18%.
213 (d)
Plants, unlike animals have no specialised organs
for gaseous exchange but they have stomata and
lenticels for this purpose
214 (a)
Citric acid cycle was discovered by British
Chemist Hans Kreb’s in 1937
215 (d)
Acetobacter sp. Are of particular importance,
commercially they also used in the production of
vinegar by converting the ethanol in the wine to
acetic acid.
216 (d)
In glycolysis, two molecules of ATP are consumed
initially in converting glucose to fructose 1, 6
bisphosphate. Two triose phosphate molecules
are formed from one glucose molecule. Four
molecules of ATP are produced at substrate level
phosphorylation. Therefore, net gain of ATP is
2ATP×2−2ATP = 2.
217 (b)
The synthesis of ATP from ADP is called
phosphorylation. Substrate level phosphorylation
is directly linked to liberation of energy in
chemical reaction of respiration, e.g., formation of
GTP is Krebs’ cycle.
218 (a)
Malonate an analogue of succinate is a strong
competitive inhibitor of succinate dehydrogenase
and, therefore, blocks the activity of citric acid
cycle.

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219 (d)
There is a total gain of 38 ATP molecules during
aerobic respiration of one molecules of glucose.
Out of these, two molecules of ATP are required
for transporting the NADH produced in glycolysis
(in cytoplasm) into the mitochondria for further
oxidation. Hence, the net gain of ATP is 36
molecules.
220 (a)
Animals are heterotrophic, i.e., they obtain food
from plants directly (herbivores) or indirectly
(carnivores)
221 (c)
During Kreb’s cycle as a result of formation of
6NADH, 18 ATP are produced through ETS in
mitochondria
222 (c)
In glycolysis, one molecule of glucose changes into
two molecules of pyruvic acid. Glycolysis takes
place in cytoplasm.
223 (a)
Electron transport system occurs in inner
mitochondrial membrane. Electron from NADH
produced in the mitochondrial matrix during
citric acid cycle are oxidised by an NADH
dehydrogenase (complex) and electrons are then
transferred to ubiquinone located within the
inner membrane
224 (b)
Krebs’ cycle is also known as citric acid cycle (first
compound of Krebs’ cycle) or Tricarboxylic acid
cycle (TCA). This cycle takes place in the matrix of
mitochondria because all necessary enzymes are
found in the matrix of mitochondria.
225 (c)
Ratio of the volume of carbon dioxide liberated to
the volume of oxygen absorbed during respiration
is called Respiratory Quotient (RQ)
Carbohydrate – One
Fat, protein – Less than one
Organic acid – More than one
Succulents – Zero
226 (d)
Calorie is the unit of heat
227 (c)
Aspergillus is used to prepare the Roquefort
cheese.
228 (c)
Cellular respiration is the process, in which
energy stored in a glucose molecule is released by
oxidation. Hydrogen atoms are lost by glucose and
gained by oxygen.
229 (a)
The term ‘glycolysis’ has originated from the
greek words, glycos for sugar and lysis for
splitting
230 (d)
Mitochondria are called power house of cell, as
the food material is gradually oxidised and energy
generated is stored in the form of ATP. The
enzymes for Krebs’ cycle (aerobic respiration)
and fatty acid oxidation are found in the matrix of
mitochondria.
231 (b)
Incomplete breakdown of sugar in anaerobic
respiration forms alcohol and dioxide.
232 (c)
The total energy trapped per gm mole of glucose
is 1292 kJ or 309.7 kcal with on efficiency of 45%
233 (b)
Glycolysis is an essential and first path of
respiration. It is common in both aerobic and
anaerobic respiration and occurs in the cytosol of
all living cells of prokaryotes as well as
eukaryotes.
234 (b)
Synthesis is anabolism
235 (b)
Oxalosuccinic acid -6 C-compound
Malate -4 C-compound
𝛼-ketoglutarate -5 C-compound
Pyruvic acid -3 C-compound
236 (d)
Respiratory chain for oxidative phosphorylation
is located in the inner membrane of mitochondrial
envelope.
237 (d)
In both lactic acid and alcohol fermentation 7% of
the energy in glucose is released and all of it is
trapped as high energy bonds of ATP
238 (d)
There is a sequential, orderly pathway
functioning, with one substrate forming the next
and with glycolysis TCA cycle and ETS pathway
following one after another
239 (a)
Sucrose is converted into glucose and fructose by
the enzyme invertase and these two
monosaccharide readily enter the glycolytic
pathway

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240 (b)
Triolein is unsaturated glyceride, whereas
tripalmitin is a saturated glyceride. The required
number of oxygen molecule for oxidation of
unsaturated glyceride is always more than for
saturated glyceride.
241 (a)
The pathway through which the electron passes
from one carrier to another is called the electron
transport system. It is operative in the inner
mitochondrial membrane
242 (d)
Tricarboxylic acid cycle is also known as citric
acid cycle or Krebs’ cycle. This is an aerobic
process which takes place in the matrix of
mitochondria. Krebs discovered this cycle in 1937

So, this is also known as Hens Krebs’ cycle.
243 (a)
It is the fact that in respiration glucose is broken
down in oxidation within the cell and CO2, water
and energy is released therefore the suitable
equations is
C6H12O6+6O2→+6CO2+6H2O+ Energy
244 (a)
Glycolysis, Krebs’ cycle and electron transport
system are meant for ATP synthesis in different
steps. ATP is the energy currency of cell.
245 (a)
There is one step in glycolysis where NADH+H+
is formed from NAD+ when 3-
phosphoglyceraldehyde (PGAL) is converted to 1,
3- bisphosphoglycerate (BPGA)

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