NEET Topic-wise & A
Topic 1 BREATHING IN PLANTS
Model Questions
01. Cellular respiration is the
(1) Oxidation of food materials within the cells to release ATP.
(2) Oxidation of food materials within the cells to release energy for ATP synthesis.
(3) Breaking of C-C bonds of complex molecules within the cell to release energy for ATP synthesis.
(4) Both b & c.
✅ 4) Both b & c.
02. The energy released by cellular respiration is used for
(1) Absorption & transport
(2) Movement & reproduction
(3) Breathing & movement
(4) All the above
✅ (4) All the above
03. Select the false statement from the following.
(1) For respiration, plants get CO₂ and give out O₂.
(2) Ultimate source of food that is respired is photosynthesis.
(3) The compounds that are oxidized during respiration are called respiratory substrates.
(4) The energy released is not used directly but is used to synthesize ATP.
✅ (1) For respiration, plants get CO₂ and give out O₂.
04. In plants, gas exchange occurs via
(1) Leaf lamina & Lenticels
(2) Stomata & Lenticels
(3) Stomata & Leaf lamina
(4) Stomata only
✅ (2) Stomata & Lenticels
05. Plants need no specialized respiratory organs because
(1) Each plant part takes care of its own gas-exchange needs.
(2) In plants, there is only aery low gas exchange as compared to that of animals.
(3) Leaves are adapted for maximum gas exchange during photosynthesis.
(4) All the above.
✅ (4) All the above.
06. Cellular respiration can be summarized as
(1) 6C₆H₁₂O₆ + 6O₂ → 6CO₂ + H₂O + Heat
(2) C₆H₁₂O₆ + O₂ → 6CO₂ + 6H₂O + Energy
(3) C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
(4) 6CO₂ + H₂O → 6C₆H₁₂O₆ + 6O₂ + Heat
✅ (3) C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
Topic 2 GLYCOLYSIS (EMP PATHWAY)
NEET: Previous Years Questions
07. Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: ATP is used at two steps in glycolysis.
Reason R: First ATP is used in converting glucose into glucose-6-phosphate and second ATP is used in conversion of fructose-6-phosphate into fructose-1-6-diphosphate.
In the light of the above statements, choose the correct answer from the options given below:
(1) Both A and R are true but R is NOT the correct explanation of A.
(2) A is true but R is false.
(3) A is false but R is true.
(4) Both A and R are true and R is the correct explanation of A. (NEET 2023)
✅ (4) Both A and R are true and R is the correct explanation of A.
08. Conversion of glucose to glucose-6-phosphate, the first irreversible reaction of glycolysis, is catalyzed by:
(1) Aldolase
(2) Hexokinase
(3) Enolase
(4) Phosphofructokinase (NEET 2019)
✅ (2) Hexokinase
Model Questions
09. Glycolysis (EMP pathway) is the
(1) Complete oxidation of glucose to 2 molecules of pyruvic acid (C₃H₄O₃) in the absence of O₂.
(2) Partial oxidation of glucose to 2 molecules of pyruvic acid (C₃H₄O₃) in the absence of O₂.
(3) Partial oxidation of glucose to 4 molecules of pyruvic acid (C₃H₄O₃) in the presence of O₂.
(4) Complete oxidation of glucose to 2 molecules of pyruvic acid (C₃H₄O₃) in the presence of O₂.
✅ (2) Partial oxidation of glucose to 2 molecules of pyruvic acid (C₃H₄O₃) in the absence of O₂.
10. Glycolysis occurs in
(1) Cytoplasm of prokaryotes and mitochondria of eukaryotes
(2) Mitochondrial matrix of prokaryotes and cytoplasm of eukaryotes
(3) Cytoplasm of prokaryotes and eukaryotes
(4) Mitochondria of prokaryotes & eukaryotes
✅ (3) Cytoplasm of prokaryotes and eukaryotes
11. Scheme of glycolysis was given by
(1) Gustav Embden, Otto Meyerhof & J. Parnas
(2) Hans Krebs
(3) Engelmann, Meyerhof & Priestly
(4) Hatch and Slack
✅ (1) Gustav Embden, Otto Meyerhof & J. Parnas
12. In anaerobes, the only process in respiration is
(1) Krebs’ cycle
(2) EMP pathway
(3) Lactic acid fermentation
(4) Oxidative phosphorylation
✅ (2) EMP pathway
13. In plants, glucose is derived from
(1) Protein and starch
(2) Lipid and sucrose
(3) Sucrose and storage carbohydrates
(4) Lipid and storage carbohydrates
✅ (3) Sucrose and storage carbohydrates
14. Sucrose is converted to glucose & fructose by an enzyme
(1) Invertase
(2) Sucrase
(3) Hexokinase
(4) Both a & b
✅ (4) Both a & b
15. The 2 monosaccharides that readily enter glycolytic pathway are
(1) Glucose & sucrose
(2) Glucose & fructose
(3) Fructose & galactose
(4) Galactose & glucose
✅ (2) Glucose & fructose
16. Glucose & fructose are phosphorylated to form glucose-6-phosphate by the enzyme
(1) Hexokinase
(2) Invertase
(3) ATP synthase
(4) Phosphofructokinase
✅ (1) Hexokinase
17. EMP pathway includes
(1) 9 steps
(2) 10 steps
(3) 11 steps
(4) 12 steps
✅ (2) 10 steps
18. In glycolysis, ATP is utilized during the conversion of
(1) Glucose into glucose 6-phosphate and glucose 6-phosphate to fructose 6-phosphate.
(2) Glucose into glucose 6-phosphate and Fructose 6-phosphate to fructose 1, 6-diphosphate.
(3) Fructose 1, 6-diphosphate to PGAL and PGAL to DPGA.
(4) PGAL to DPGA and DPGA to PGA.
✅ (2) Glucose into glucose 6-phosphate and Fructose 6-phosphate to fructose 1, 6-diphosphate.
19. In glycolysis, during the conversion of PGAL to DPGA,
(1) 2 redox-equivalents (2 H-atoms) are removed from PGA and transferred to NAD⁺ forming NADH + H⁺.
(2) 2 redox-equivalents (2 H-atoms) are removed from PGAL and transferred to NADH + H⁺ forming NAD⁺.
(3) 2 redox-equivalents (2 H-atoms) are removed from PGAL and transferred to NAD⁺ forming NADH + H⁺.
(4) 2 redox-equivalents (2 H-atoms) are removed from DPGA and transferred to NAD⁺ forming NADH + H⁺.
✅ (3) 2 redox-equivalents (2 H-atoms) are removed from PGAL and transferred to NAD⁺ forming NADH + H⁺.
20. In EMP pathway, ATP molecules are formed when
(1) PGAL becomes BPGA and BPGA becomes PGA
(2) PGA becomes BPGA and PA becomes PEP
(3) PGAL becomes BPGA and PEP becomes PA
(4) BPGA becomes PGA and PEP becomes PA
✅ (4) BPGA becomes PGA and PEP becomes PA
21. In glycolysis, how many ATP molecules are directly synthesised from one glucose molecule?
(1) 2
(2) 4
(3) 8
(4) 36
✅ (1) 2
22. The key product of glycolysis is
(1) Pyruvic acid
(2) Acetyl CoA
(3) PEP
(4) PGAL
✅ (1) Pyruvic acid
23. In human, pyruvic acid is handled in
(1) Aerobic respiration (Krebs’ cycle).
(2) Aerobic respiration & Alcoholic fermentation.
(3) Aerobic respiration & Lactic acid fermentation.
(4) Aerobic respiration, Alcoholic fermentation & Lactic acid fermentation.
✅ (3) Aerobic respiration & Lactic acid fermentation.
Topic 3 FERMENTATION (ANAEROBIC RESPIRATION)
Model Questions
24. Regarding anaerobic respiration, which statement is wrong?
(1) The enzymes, pyruvic acid decarboxylase & alcohol dehydrogenase catalyse alcoholic fermentation.
(2) Yeasts poison themselves to death when the concentration of alcohol reaches about 13%.
(3) In the last step of alcoholic and lactic acid fermentations, the NAD⁺ becomes NADH+H⁺.
(4) In animals, when oxygen is inadequate, pyruvic acid in muscle cells is reduced to lactic acid by lactate dehydrogenase.
✅ (3) In the last step of alcoholic and lactic acid fermentations, the NAD⁺ becomes NADH + H⁺.
25. Net ATP production from fermentation of one glucose molecule is
(1) 2
(2) 4
(3) 36
(4) 38
✅ (1) 2
26. The drawback of fermentation process is
(1) Energy production is limited.
(2) Less than 7% energy in glucose is released and not all of it is trapped as high energy bonds of ATP.
(3) Hazardous products such as acid or alcohol are formed.
(4) All the above.
✅ (4) All the above.
27. In which of the following processes, CO₂ is not released?
(1) Aerobic respiration in plants
(2) Aerobic respiration in animals
(3) Alcoholic fermentation
(4) Lactate fermentation
✅ (4) Lactate fermentation
28. Choose the correct combination of labeling the molecules involved in the pathway of anaerobic respiration in yeast.
(1) A- Acetaldehyde, B- CO₂, C- Ethanol
(2) A- Ethanol, B- CO₂, C- Acetaldehyde
(3) A- Ethanol, B- Acetaldehyde, C- CO₂
(4) A- CO₂, B- Ethanol, C- Acetaldehyde
✅ (3) A- Ethanol, B- Acetaldehyde, C- CO₂
29. Select the mismatching pair.
(1) EMP pathway: Cytoplasm
(2) TCA cycle: Mitochondrial matrix
(3) Oxidative decarboxylation: Mitochondrial matrix
(4) ETS: Outer mitochondrial membrane
✅ (4) ETS: Outer mitochondrial membrane
Topic 4 AEROBIC RESPIRATION
NEET: Previous Years Questions
30. Identify the step in tricarboxylic acid cycle, which does not involve oxidation of substrate. (NEET 2024)
(1) Malic acid → Oxaloacetic acid
(2) Succinic acid → Malic acid
(3) Succinyl-CoA → Succinic acid
(4) Isocitrate → α-ketoglutaric acid
✅ (3) Succinyl-CoA → Succinic acid
31. Match List I with List II: (NEET 2024)
Choose the correct answer from the options given below:
(1) A-I, B-II, C-III, D-IV
(2) A-II, B-I, C-IV, D-III
(3) A-III, B-IV, C-I, D-II
(4) A-IV, B-III, C-II, D-I
✅ (2) A-II, B-I, C-IV, D-III
32. Match List I with List II: (NEET 2023)
Choose the correct answer from the options given below:
(1) A-II, B-IV, C-I, D-III
(2) A-III, B-I, C-II, D-IV
(3) A-II, B-IV, C III, D-I
(4) A-III, B-IV, C-II, D-I
✅ (3) A-II, B-IV, C III, D-I
33. Which of the following statements is incorrect?
(1) During aerobic respiration, role of oxygen is limited to the terminal stage.
(2) In ETC (Electron Transport Chain), one molecule of NADH + H⁺ gives rise to 2 ATP molecules, and one FADH₂ gives rise to 3 ATP molecules.
(3) ATP is synthesized through complex V.
(4) Oxidation-reduction reactions produce proton gradient in respiration. (NEET 2021)
✅ (2) In ETC (Electron Transport Chain), one molecule of NADH + H⁺ gives rise to 2 ATP molecules, and one FADH₂ gives rise to 3 ATP molecules.
34. The number of substrate level phosphorylation in one turn of citric acid cycle is: (NEET 2020)
(1) Two
(2) Three
(3) Zero
(4) One
✅ (4) One
35. Which of these statements is incorrect? (NEET 2018)
(1) Enzymes of TCA cycle are present in mitochondrial matrix.
(2) Glycolysis occurs in cytosol.
(3) Glycolysis operates as long as it is supplied with NAD that can pick up hydrogen atoms.
(4) Oxidative phosphorylation takes place in outer mitochondrial membrane.
✅ (4) Oxidative phosphorylation takes place in outer mitochondrial membrane
36. Which of the following statements regarding mitochondria is incorrect? (NEET 2019)
(1) Outer membrane is permeable to monomers of carbohydrates fats and proteins.
(2) Enzymes of electron transport are embedded in outer membrane.
(3) Inner membrane is convoluted with infoldings.
(4) Mitochondrial matrix contains single circular DNA molecule and ribosomes.
✅ (2) Enzymes of electron transport are embedded in outer membrane.
37. Respiratory Quotient (RQ) value of tripalmitin is:
(1) 0.9
(2) 0.7
(3) 0.07
(4) 0.09 (NEET 2019)
✅ (2) 0.7
38. What is the role of NAD⁺ in cellular respiration?
(1) It functions as an enzyme
(2) It functions as an electron carrier
(3) It is a nucleotide source for ATP synthesis
(4) It is the final electron acceptor for anaerobic respiration (NEET 2018)
✅ (2) It functions as an electron carrier
39. Which statement is wrong for Krebs’ cycle?
(1) There is one point in the cycle where FAD+ is reduced to FADH₂.
(2) During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised.
(3) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
(4) There are three points in the cycle where NAD⁺ is reduced to NADH + H⁺ (NEET 2017)
✅ (3) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
40. Oxidative phosphorylation is
(1) formation of ATP by transfer of phosphate group from a substrate to ADP
(2) oxidation of phosphate group in ATP
(3) addition of phosphate group to ATP
(4) formation of ATP by energy released from electrons removed during substrate oxidation. (NEET-II 2016)
✅ (4) formation of ATP by energy released from electrons removed during substrate oxidation.
41. Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins?
(1) Glucose-6-phosphate
(2) Fructose 1, 6-bisphosphate
(3) Pyruvic acid
(4) Acetyl CoA (NEET-II 2016)
✅ (4) Acetyl CoA
Model Questions
42. For aerobic respiration, the pyruvate is transported
(1) From the mitochondria into the cytoplasm.
(2) From the cytoplasm into the mitochondria.
(3) From the cytoplasm into the ribosome.
(4) From the ribosome into the cytoplasm.
✅ (2) From the cytoplasm into the mitochondria.
43. The crucial events in aerobic respiration are:
(1) Complete oxidation of pyruvate on the inner membrane of mitochondria & passing on of electrons on the outer membrane of mitochondria.
(2) Oxidative decarboxylation of pyruvate in the matrix of mitochondria & passing on of electrons in the outer membrane of mitochondria.
(3) Complete oxidation of pyruvate in the matrix of mitochondria & passing on of electrons on the inner membrane of mitochondria.
(4) Oxidative decarboxylation of pyruvate in the outer membrane of mitochondria & passing on of electrons on the inner membrane of mitochondria.
✅ (3) Complete oxidation of pyruvate in the matrix of mitochondria & passing on of electrons on the inner membrane of mitochondria.
44. Complete oxidation of pyruvate by stepwise removal of all the hydrogen atoms leaves
(1) 2 CO₂ molecules
(2) 4 CO₂ molecules
(3) 6 CO₂ molecules
(4) 3 CO₂ molecules
✅ (4) 3 CO₂ molecules
45. Pyruvate (pyruvic acid) enters mitochondrial matrix and undergoes
(1) Oxidative phosphorylation in presence pyruvic dehydrogenase.
(2) Oxidative decarboxylation in presence pyruvic dehydrogenase.
(3) Oxidative decarboxylation in presence ATP synthase.
(4) Oxidative phosphorylation in presence ATP synthase.
✅ (2) Oxidative decarboxylation in presence pyruvic dehydrogenase.
46. During oxidative decarboxylation of pyruvic acid, how many NADH molecules are produced from 2 pyruvic acid molecules?
(1) 2
(2) 3
(3) 4
(4) 5
✅ (1) 2
47. Tricarboxylic Acid (TCA) Cycle or Citric acid cycle was first elucidated by
(1) Embden, Meyerhof & Parnas
(2) Hans Krebs
(3) Engelmann, Meyerhof & Priestly
(4) Hatch and Slack
✅ (2) Hans Krebs
48. Which statement is wrong for Krebs’ cycle?
(1) There is one point in the cycle where FAD+ is reduced to FADH₂.
(2) During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised.
(3) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
(4) There are 3 points in the cycle where NAD⁺ is reduced to NADH + H⁺.
✅ (3) The cycle starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.
49. In which one of the following steps of citric acid cycle, FAD⁺ is reduced to FADH₂?
(1) Pyruvate → Acetyl Coenzyme A
(2) Succinic acid → Malic acid
(3) Malic acid → Oxaloacetic acid
(4) Citric acid → a-ketoglutaric acid
✅ (2) Succinic acid → Malic acid
50. In the electron transport system (ETS) present in the inner mitochondrial membrane, complexes I and IV are
(1) NADH dehydrogenase and FADH₂ respectively
(2) FADH₂ and NADH dehydrogenase respectively
(3) NADH dehydrogenase and cytochrome oxidase complex respectively
(4) NADH dehydrogenase and ATP synthase respectively
✅ (3) NADH dehydrogenase and cytochrome oxidase complex respectively
51. In mitochondria, protons accumulate in the
(1) Outer membrane
(2) Inner membrane
(3) Intermembrane space
(4) Matrix
✅ (3) Intermembrane space
52. Which acts as a mobile carrier of electrons between complex III and IV?
(1) Cytochrome c
(2) Cytochrome a
(3) Cytochrome a3
(4) Cytochrome bc1
✅ (1) Cytochrome c
53. Oxidation of 1 NADH and 1 FADH₂ can produce
(1) 2ATP & 3 ATP respectively
(2) 3 ATP & 1 ATP respectively
(3) 1 ATP & 2 ATP respectively
(4) 3 ATP & 2 ATP respectively
✅ (4) 3 ATP & 2 ATP respectively
54. In ETS, the final hydrogen acceptor is
(1) Oxygen
(2) NAD
(3) FAD
(4) CoA
✅ (1) Oxygen
55. In mitochondria, site for ATP synthesis is
(1) F₀
(2) F₁
(3) Matrix
(4) Ion channels
✅ (2) F₁
56. Label P, Q, R and S in the following figure.
(1) P= ATP, Q= Inner mitochondrial membrane, R= F₀, S= F₁.
(2) P= ATP, Q= Outer mitochondrial membrane, R= F₁, S= F₀.
(3) P= 2H⁺, Q= Outer mitochondrial membrane, R= F₁, S= F₀.
(4) P= 2H⁺, Q= Inner mitochondrial membrane, R= F₀, S= F₁.
✅ (4) P= 2H⁺, Q= Inner mitochondrial membrane, R= F₀, S= F₁.
57. Out of 38 molecules of ATP produced upon aerobic respiration of glucose, the break up in ATP production is
(1) Glycolysis= 2, oxidative decarboxylation= 6, Krebs’ cycle= 30
(2) Glycolysis= 8, oxidative decarboxylation= 6, Krebs’ cycle= 24
(3) Glycolysis= 8, oxidative decarboxylation= 10, Krebs’ cycle= 20
(4) Glycolysis= 2, oxidative decarboxylation= 12, Krebs’ cycle= 24
✅ (2) Glycolysis= 8, oxidative decarboxylation= 6, Krebs’ cycle= 24
58. For respiration, all carbohydrates are first converted to
(1) Glucose
(2) Fructose
(3) Pyruvic acid
(4) ATP
✅ (1) Glucose
59. Pick out the wrong statement.
(1) Fatty acids are degraded to acetyl CoA and enter the TCA cycle.
(2) Glycerol is converted to glucose and enters the respiratory pathway.
(3) Each amino acid, after deamination, enters the pathway at some stage in the Krebs’ cycle or as pyruvate or acetyl CoA.
(4) When the organism needs to synthesise fatty acids, acetyl CoA withdraw from the respiratory pathway.
✅ (2) Glycerol is converted to glucose and enters the respiratory pathway.
60. The respiratory pathway is appropriately termed
(1) Parabolic
(2) Amphibolic
(3) Anabolic
(4) Catabolic
✅ (2) Amphibolic
61. Select the wrong statement.
(1) Respiratory quotient (RQ) is the ratio of the volume of O₂ consumed to the volume of CO₂ evolved.
(2) RQ for carbohydrates is 1 because equal amounts of CO₂ and O₂ are evolved and consumed, respectively.
(3) Pure proteins or fats are never used as respiratory substrates.
(4) RQ for proteins is 0.9 and for fats is less than 1.
✅ (1) Respiratory quotient (RQ) is the ratio of the volume of O₂ consumed to the volume of CO₂ evolved.