Lesson 3.5.1.1

3.5.1.1 Light-dependent and light-independent reactions Quiz: AQA Biology, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 3.5.1.1, Light-dependent and light-independent reactions: 20 multiple choice questions for the AQA Biology (7402), Unit 5: Energy transfers in and between organisms, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What happens to chlorophyll when it absorbs light in the light-dependent reaction?

    • It undergoes photoionisation, releasing electrons
    • It combines with rubisco to form GP
    • It is reduced by carbon dioxide
    • It is hydrolysed into glucose

  2. Which substance is produced by the photolysis of water in the light-dependent reaction?

    • Carbon dioxide
    • Glucose
    • Ribulose bisphosphate
    • Oxygen

  3. Which enzyme catalyses the fixation of carbon dioxide with RuBP in the light-independent reaction?

    • Rubisco
    • ATP synthase
    • Lactate dehydrogenase
    • Acetylcoenzyme A synthase

  4. What is the product of carbon dioxide reacting with RuBP in the light-independent reaction?

    • Two molecules of glycerate 3-phosphate
    • One molecule of glucose
    • Two molecules of pyruvate
    • Two molecules of triose phosphate

  5. Which two products of the light-dependent reaction are used to reduce GP to triose phosphate?

    • ATP and reduced NADP
    • Oxygen and protons
    • Electrons and carbon dioxide
    • Glucose and water

  6. In the light-dependent reaction, how is ATP produced?

    • By substrate-level phosphorylation in the stroma
    • By the breakdown of glucose in the cytoplasm
    • By chemiosmosis, as protons pass through ATP synthase embedded in chloroplast membranes
    • By direct reaction of carbon dioxide with water

  7. What is the role of the Calvin cycle as described in the specification?

    • To store carbon dioxide as starch
    • To break down glucose to pyruvate
    • To regenerate RuBP from some of the triose phosphate
    • To split water into oxygen and protons

  8. Why is ATP from the light-dependent reaction used in the light-independent reaction?

    • It fixes carbon dioxide into GP
    • It splits water to release oxygen
    • It absorbs light energy for photoionisation
    • It provides energy to reduce GP to triose phosphate

  9. Calculate the number of ATP and reduced NADP molecules needed to fix 3 molecules of carbon dioxide into one net triose phosphate, using the standard values of 9 ATP and 6 reduced NADP.

    • 18 ATP and 12 reduced NADP
    • 3 ATP and 2 reduced NADP
    • 6 ATP and 4 reduced NADP
    • 9 ATP and 6 reduced NADP

  10. Which molecule is used to carry protons and electrons, and is reduced in the light-dependent reaction?

    • RuBP
    • Pyruvate
    • Glucose
    • NADP

  11. Which of the following statements about the light-independent reaction is correct?

    • It takes place using reduced NADP and ATP from the light-dependent reaction
    • It takes place in the thylakoid membranes
    • It produces oxygen as a product
    • It requires light directly to fix carbon dioxide

  12. Which product of photosynthesis is formed directly from triose phosphate?

    • Useful organic substances such as glucose or other sugars
    • Carbon dioxide
    • Electrons
    • Oxygen

  13. In chloroplasts, electrons released by photoionisation are passed along an electron transfer chain. What does this energy drive?

    • The release of lactate
    • The breakdown of water into carbon dioxide
    • The conversion of GP to RuBP directly
    • Movement of protons across the membrane, which helps produce ATP

  14. Which of the following correctly lists the products of the light-dependent reaction?

    • ATP, reduced NADP and oxygen
    • Pyruvate, reduced NAD and water
    • Glucose, ATP and carbon dioxide
    • GP, triose phosphate and oxygen

  15. The light-independent reaction is described as using carbon dioxide and energy from the light-dependent reaction. Which is the carbon source for the sugar formed?

    • Oxygen
    • Carbon dioxide
    • Protons
    • ATP

  16. A student states that the light-independent reaction only occurs in the dark. Which correction is needed?

    • It is a reaction that breaks down glucose
    • It requires oxygen to be present in order to start
    • It occurs only in the dark because light is absent
    • It does not directly require light but depends on products of the light-dependent reaction, which does require light

  17. Electrons released by chlorophyll are used to reduce NADP. Why must the chlorophyll be replaced with electrons from photolysis of water?

    • Chlorophyll has to be regenerated from RuBP
    • Chlorophyll must receive electrons from water to replace those it has lost, keeping photoionisation going
    • Chlorophyll produces oxygen which must be removed
    • Chlorophyll is consumed to make triose phosphate

  18. Which molecule is the first stable product of carbon fixation in the Calvin cycle?

    • Glucose
    • Glycerate 3-phosphate
    • Ribulose bisphosphate
    • Pyruvate

  19. In the Calvin cycle, what happens to most of the triose phosphate produced?

    • It is all converted to oxygen
    • It is all broken down in glycolysis
    • Some is used to regenerate RuBP and some is converted to useful organic substances
    • It is released as carbon dioxide

  20. Approximately how many carbon dioxide molecules must be fixed to produce one net triose phosphate molecule in the Calvin cycle?

    • 2
    • 1
    • 6
    • 3

All AQA Biology quizzes