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AS & A Level · AS/A Level

Biology

Respiration and photosynthesis

Name: ____________________Date: October 10, 2026
  1. 1.

    Explain why ATP is useful as an immediate energy-transfer molecule rather than simply calling it an energy store.

    [3 marks] · no calculator
  2. 2.

    State the roles of oxygen and reduced NAD in aerobic oxidative phosphorylation.

    [3 marks] · no calculator
  3. 3.

    A respirometer absorbs CO2 and records 3.6 cm^3 oxygen uptake by 2.0 g of seeds in 12 minutes. Calculate uptake rate per gram per minute.

    [3 marks]
  4. 4.

    Explain how ATP synthase produces ATP in a chloroplast, including the source and direction of the proton gradient.

    [3 marks] · no calculator
  5. 5.

    An uncoupler allows protons to cross the inner mitochondrial membrane without ATP synthase. Predict its effects on the proton gradient and ATP yield, and explain why electron flow may continue.

    [4 marks] · no calculator
  6. 6.

    A plant exposed to light but deprived of CO2 accumulates reduced NADP while carbon fixation slows. Explain the connection and why light alone cannot sustain carbohydrate synthesis.

    [4 marks] · no calculator

Original, unofficial practice questions from SubjectScout — not official past-paper questions.

Marking points are indicative, not an official mark scheme. Accept equivalent valid methods and supported interpretations that address the task; award each mark once without requiring the model wording.