Respiration in Plants – Daily Practice Problem (DPP)

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🎯 NEET 2026 Daily Practice Problem (DPP)

Topic: Respiration in Plants | 20 High-Yield MCQs

Q1. The common pathway for both aerobic and anaerobic respiration is:

  1. Krebs cycle
  2. Glycolysis
  3. Electron transport system
  4. Oxidative phosphorylation
✅ View Answer & Explanation

Correct Answer: (2) Glycolysis
Explanation: Glycolysis occurs in the cytoplasm and does not require oxygen, making it the common first step for all living organisms.

Q2. The scheme of glycolysis was given by:

  1. Gustav Embden
  2. Otto Meyerhof
  3. J. Parnas
  4. All of these
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Correct Answer: (4) All of these
Explanation: Glycolysis is also known as the EMP pathway, named after Embden, Meyerhof, and Parnas.

Q3. What is the end product of Glycolysis?

  1. Acetyl CoA
  2. Citric acid
  3. Pyruvic acid
  4. Glucose-6-phosphate
✅ View Answer & Explanation

Correct Answer: (3) Pyruvic acid
Explanation: One molecule of glucose (6C) is broken down into two molecules of pyruvic acid (3C) during glycolysis.

Q4. The enzyme which catalyzes the conversion of glucose to glucose-6-phosphate is:

  1. Phosphofructokinase
  2. Hexokinase
  3. Aldolase
  4. Pyruvate kinase
✅ View Answer & Explanation

Correct Answer: (2) Hexokinase
Explanation: Hexokinase is the first enzyme in glycolysis that phosphorylates glucose using one ATP.

Q5. In yeast, fermentation results in the production of:

  1. Ethanol and CO_2
  2. Lactic acid
  3. Methanol
  4. Citric acid
✅ View Answer & Explanation

Correct Answer: (1) Ethanol and CO_2
Explanation: Anaerobic respiration in yeast (alcoholic fermentation) converts pyruvic acid into ethanol and carbon dioxide.

Q6. The site of Tricarboxylic Acid (TCA) cycle in eukaryotes is:

  1. Cytoplasm
  2. Mitochondrial matrix
  3. Inner mitochondrial membrane
  4. Perisomes
✅ View Answer & Explanation

Correct Answer: (2) Mitochondrial matrix
Explanation: The enzymes for the Krebs cycle are located in the matrix of the mitochondria.

Q7. The ‘Link reaction’ converts Pyruvate into:

  1. Oxaloacetic acid
  2. Citric acid
  3. Acetyl CoA
  4. Malic acid
✅ View Answer & Explanation

Correct Answer: (3) Acetyl CoA
Explanation: Oxidative decarboxylation of pyruvate by pyruvate dehydrogenase produces Acetyl CoA, which then enters the Krebs cycle.

Q8. The first member of the TCA cycle is:

  1. Acetyl CoA
  2. Citric acid
  3. Oxaloacetic acid (OAA)
  4. Succinic acid
✅ View Answer & Explanation

Correct Answer: (2) Citric acid
Explanation: The cycle starts with the condensation of acetyl group with OAA and water to yield citric acid. Hence it is called the Citric Acid Cycle.

Q9. How many CO_2 molecules are released in one turn of the Krebs cycle?

  1. 1
  2. 2
  3. 3
  4. 4
✅ View Answer & Explanation

Correct Answer: (2) 2
Explanation: Two decarboxylation steps occur in the Krebs cycle (Isocitrate to alpha-ketoglutarate and alpha-ketoglutarate to Succinyl CoA).

Q10. Cytochrome c oxidase complex (Complex IV) contains cytochromes:

  1. b and c_1
  2. a and a_3
  3. c only
  4. f and b_6
✅ View Answer & Explanation

Correct Answer: (2) a and a_3
Explanation: Complex IV contains cytochromes a and a_3, and two copper centres.

Q11. The final electron acceptor in aerobic respiration is:

  1. CO_2
  2. Water
  3. Oxygen
  4. NAD+
✅ View Answer & Explanation

Correct Answer: (3) Oxygen
Explanation: Oxygen acts as the final hydrogen acceptor, which results in the formation of water.

Q12. For every FADH_2 oxidized in ETS, how many ATP molecules are formed?

  1. 1
  2. 2
  3. 3
  4. 4
✅ View Answer & Explanation

Correct Answer: (2) 2
Explanation: Oxidation of one NADH yields 3 ATP, while oxidation of one FADH_2 yields 2 ATP molecules.

Q13. The Respiratory Quotient (RQ) for Tripalmitin (a fat) is:

  1. 1.0
  2. 0.9
  3. 0.7
  4. 1.4
✅ View Answer & Explanation

Correct Answer: (3) 0.7
Explanation: Fats have an RQ less than 1. For proteins it is about 0.9, and for carbohydrates it is 1.0.

Q14. The total net gain of ATP from one molecule of glucose during aerobic respiration is:

  1. 2
  2. 36 or 38
  3. 8
  4. 30
✅ View Answer & Explanation

Correct Answer: (2) 36 or 38
Explanation: Depending on the shuttle system used to transport cytoplasmic NADH, the total yield is 36 or 38 ATP.

Q15. Which molecule acts as the ‘Mobile Electron Carrier’ in the inner mitochondrial membrane?

  1. Ubiquinone (CoQ)
  2. Cytochrome c
  3. Both 1 and 2
  4. ATP synthase
✅ View Answer & Explanation

Correct Answer: (3) Both 1 and 2
Explanation: Ubiquinone and Cytochrome c are mobile carriers that transfer electrons between the fixed complexes of the ETS.

Q16. The enzyme complex V in ETS is:

  1. NADH dehydrogenase
  2. Succinate dehydrogenase
  3. Cytochrome bc1 complex
  4. ATP synthase
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Correct Answer: (4) ATP synthase
Explanation: Complex V is ATP synthase, which utilizes the proton gradient to synthesize ATP from ADP and Pi.

Q17. In the ETS, electrons from NADH are first accepted by:

  1. Complex I
  2. Complex II
  3. Complex III
  4. Complex IV
✅ View Answer & Explanation

Correct Answer: (1) Complex I
Explanation: Complex I is NADH dehydrogenase, which oxidizes NADH produced in the matrix.

Q18. Respiration is considered an ‘Amphibolic pathway’ because:

  1. It involves only catabolism
  2. It involves only anabolism
  3. It involves both catabolism and anabolism
  4. It occurs in both plants and animals
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Correct Answer: (3) It involves both catabolism and anabolism
Explanation: Respiratory intermediates are withdrawn for the synthesis (anabolism) of other compounds, while substrates are broken down (catabolism) for energy.

Q19. During lactic acid fermentation, how much energy is released?

  1. Less than 7%
  2. More than 20%
  3. About 50%
  4. Zero energy
✅ View Answer & Explanation

Correct Answer: (1) Less than 7%
Explanation: Fermentation is an inefficient process; less than 7% of the energy in glucose is released and not all of it is trapped as ATP.

Q20. Substrate level phosphorylation in Krebs cycle yields:

  1. ATP
  2. GTP
  3. FADH2
  4. NADH
✅ View Answer & Explanation

Correct Answer: (2) GTP
Explanation: During the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesized (which is later converted to ATP).

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