Link reaction and Krebs cycle

Link reaction and Krebs cycle Quiz

Spec 7.3 · Edexcel International A Level Biology: Quiz

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  1. 1. Where in the cell does the Krebs cycle occur?

    • A. Cytoplasm
    • B. Inner mitochondrial membrane
    • C. Mitochondrial matrix
    • D. Nucleus

  2. 2. What is removed from pyruvate in the link reaction?

    • A. Carbon dioxide and hydrogen
    • B. Oxygen and water
    • C. ATP and carbon dioxide
    • D. Lactate and hydrogen

  3. 3. What is made in one turn of the Krebs cycle?

    • A. 1 CO₂, 1 reduced NAD and 3 ATP
    • B. 3 CO₂ and 2 reduced FAD
    • C. 4 reduced NAD and 2 ATP
    • D. 2 CO₂, 3 reduced NAD, 1 reduced FAD and 1 ATP

  4. 4. Why does the Krebs cycle stop if oxygen is absent?

    • A. Oxygen is a substrate of the cycle
    • B. Reduced NAD and FAD are not reoxidised, so no NAD or FAD is available
    • C. ATP is no longer needed
    • D. Carbon dioxide builds up and inhibits the cycle

  5. 5. How many carbon dioxide molecules are released from one glucose in the link reaction and Krebs cycle together?

    • A. 2
    • B. 4
    • C. 6
    • D. 8

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