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NEET-UG Biology · Class 11

Krebs cycle — NEET & JEE Questions

Krebs cycle is a topic in Respiration in Plants, a Class 11 Biology chapter of the NEET-UG syllabus. TestBudy holds 17 published NEET-UG questions on Krebs cycle, each with the marking scheme of the real paper.

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Krebs cycle MCQs with solutions

10 of the 17 published questions on this topic, exactly as they appear in a test. Answers and worked solutions come with your result rather than on this page.

  1. Question 1 · difficulty L1 · recall

    Where does the Krebs cycle occur in eukaryotic cells?

    • A. Outer mitochondrial membrane
    • B. Cytoplasm
    • C. Mitochondrial matrix
    • D. Golgi apparatus

  2. Question 2 · difficulty L2 · understanding

    Before entering the Krebs cycle, pyruvate is converted into which two-carbon compound?

    • A. Succinate
    • B. Oxaloacetate
    • C. Citrate
    • D. Acetyl-CoA

  3. Question 3 · difficulty L2 · understanding

    The Krebs cycle in aerobic respiration occurs mainly in the

    • A. mitochondrial matrix
    • B. cytoplasm
    • C. nucleus
    • D. chloroplast thylakoid

  4. Question 4 · difficulty L2 · understanding

    Acetyl-CoA enters the Krebs cycle by combining with oxaloacetate to form

    • A. citrate
    • B. pyruvate
    • C. lactate
    • D. glucose

  5. Question 5 · difficulty L3 · understanding

    Identify the step in tricarboxylic acid cycle, which does not involve oxidation of substrate.

    • A. Malic acid →\rightarrow Oxaloacetic acid
    • B. Succinic acid →\rightarrow Malic acid
    • C. Succinyl-CoA →\rightarrow Succinic acid
    • D. Isocitrate →α\rightarrow \alpha-ketoglutaric acid

  6. Question 6 · difficulty L3 · understanding

    How many times decarboxylation occurs during each TCA cycle?

    • A. Thrice
    • B. Many
    • C. Once
    • D. Twice

  7. Question 7 · difficulty L3 · understanding

    Match List I with List II: List I List II (A) Oxidative decarboxylation (I) Citrate synthase (B) Glycolysis (II) Pyruvate dehydrogenase (C) Oxidative phosphorylation (III) Electron transport system (D) Tricarboxylic acid cycle (IV) EMP pathway Choose the correct answer from the options given below :

    • A. A – II, B – IV, C – I, D – III
    • B. A – III, B – I, C – II, D – IV
    • C. A – II, B – IV, C – III, D – I
    • D. A – III, B – IV, C – II, D – I

  8. Question 8 · difficulty L3 · understanding

    Melonate inhibits the growth of pathogenic bacteria by inhibiting the activity of

    • A. Amylase
    • B. Lipase
    • C. Dinitrogenase
    • D. Succinic dehydrogenase

  9. Question 9 · difficulty L3 · understanding

    The 5-C compound formed during TCA cycle is

    • A. Fumaric acid
    • B. α\alpha-ketoglutaric acid
    • C. Oxalo succinic acid
    • D. Succinic acid

  10. Question 10 · difficulty L3 · understanding

    The number of time(s) decarboxylation of isocitrate occurs during single TCA cycle is

    • A. Four
    • B. One
    • C. Two
    • D. Three

Common mistakes in Krebs cycle

Recorded against questions in this topic that are not shown above, so none of these points at an answer you can see on this page.

  • Treating oxaloacetate as a consumed end product rather than a regenerated cycle intermediate.
  • Remembering that both reduced coenzymes are formed but mixing up their quantities.
  • Assuming pyruvate enters the Krebs cycle directly.
  • Counts the carbon dioxide released before acetyl-CoA enters the cycle.
  • Reverses the relative yields of NADH and FADH2.
  • Assumes acetyl-CoA can enter the cycle without oxaloacetate.

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