Lesson 5.2.3

5.2.3 Light-independent reactions and chloroplast structure Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.2.3, Light-independent reactions and chloroplast structure: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 5: On the Wild Side, written with Revision Ninja.

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The 20 questions

  1. What is the first step of the Calvin cycle?

    • Glucose is broken down by glycolysis
    • ADP is converted into ATP by phosphorylation
    • CO2 combines with RuBP, catalysed by RUBISCO
    • Water is split by photolysis in the stroma

  2. What is the product of carbon dioxide fixation by RuBP in the Calvin cycle?

    • Two molecules of glycerate 3-phosphate (GP)
    • One molecule of glucose formed directly
    • Two molecules of oxygen released into the air
    • Two molecules of ATP made in the stroma

  3. Which compound is reduced to glyceraldehyde 3-phosphate (GALP) in the Calvin cycle?

    • Starch
    • Ribulose bisphosphate (RuBP)
    • Oxygen
    • Glycerate 3-phosphate (GP)

  4. What role does RUBISCO have in the Calvin cycle?

    • It is the enzyme that catalyses carbon dioxide fixation
    • It is the pigment that absorbs light
    • It is the enzyme that splits water in photolysis
    • It is the carrier that moves oxygen out of the leaf

  5. Most of the triose phosphate (GALP) made in the Calvin cycle is used for:

    • Releasing oxygen into the atmosphere
    • Regenerating RuBP so that the cycle can continue
    • Directly forming the chloroplast envelope
    • Splitting water into hydrogen and oxygen

  6. Why does the Calvin cycle require ATP?

    • To split water and release oxygen
    • To make chlorophyll from carbon dioxide
    • To break down cellulose in the cell wall
    • To regenerate RuBP and to reduce GP

  7. The products of the Calvin cycle are simple sugars. Which of the following is a use for these sugars?

    • Respiration and building new biological molecules
    • Release of oxygen into the atmosphere
    • Splitting of water in photolysis
    • Production of ATP directly by photophosphorylation

  8. Which structure is the site of the light-independent reactions?

    • The thylakoid membranes
    • The cytoplasm of the cell
    • The outer envelope of the chloroplast
    • The stroma of the chloroplast

  9. What is the function of the chloroplast envelope?

    • A double membrane controlling entry and exit
    • It stores light energy in chlorophyll
    • It produces the oxygen released by photolysis
    • It contains the enzymes of the Calvin cycle in the grana

  10. Why do thylakoids form stacks called grana?

    • To remove oxygen from the chloroplast
    • To prevent the entry of carbon dioxide into the stroma
    • To store glucose in a compact form
    • To increase membrane surface area for light capture

  11. Which feature of the stroma supports the Calvin cycle?

    • It contains cellulose microfibrils that trap carbon dioxide
    • It contains chlorophyll that absorbs light directly
    • It contains the electron transport chain for photolysis
    • It holds RUBISCO and Calvin cycle intermediates

  12. A chloroplast is isolated and placed in a solution with a dye, DCPIP, in light. What does a colour change show?

    • Carbon dioxide has been converted into oxygen
    • The chloroplast has absorbed all the dye as a food source
    • The dye is reduced, showing electron transport
    • The chloroplast has stopped working in the light

  13. What is the Hill reaction used to demonstrate?

    • That cellulose is synthesised in the light
    • That isolated chloroplasts release oxygen in light
    • That respiration takes place in the chloroplast
    • That carbon dioxide is converted directly into glucose in the dark

  14. In the Hill reaction, why is an artificial electron acceptor such as DCPIP added?

    • It breaks down ATP to supply energy
    • It supplies carbon dioxide to the chloroplast
    • It replaces NADP as electron acceptor
    • It destroys chlorophyll to stop the reaction

  15. A student predicts that more light will increase the rate of colour change of DCPIP in the Hill reaction. Which variable is controlled?

    • The concentration of DCPIP and the temperature
    • The colour of the DCPIP, which is the independent variable
    • The light intensity, which is the dependent variable
    • The time the solution takes to be prepared

  16. Which sequence correctly lists the three stages of the Calvin cycle?

    • Photolysis of water, carbon fixation, then reduction of GP
    • Reduction of GP, carbon fixation, then photolysis of water
    • Regeneration of RuBP, photolysis of water, then reduction of GP
    • Carbon fixation, reduction of GP, then regeneration of RuBP

  17. Which statement about the Calvin cycle is correct?

    • It needs ATP and reduced NADP, not light directly
    • It takes place inside the thylakoid membranes
    • It requires light directly and cannot run in the dark
    • It releases oxygen as its main product

  18. Why must RuBP be regenerated continuously in the Calvin cycle?

    • It is a pigment that absorbs light for photosynthesis
    • It is a product that must be stored as starch
    • It is an enzyme that is destroyed after each reaction
    • It accepts CO2, so the cycle stops without it

  19. A plant is placed in darkness for several hours. What is the effect on the Calvin cycle?

    • It slows as ATP and reduced NADP run short
    • It produces more oxygen in the stroma
    • It speeds up to use stored carbon dioxide
    • It is unaffected because it does not need ATP

  20. Which evaluation best describes the link between chloroplast structure and photosynthesis?

    • Chloroplast structure has no link to photosynthesis
    • Thylakoids are the site of carbon fixation while the stroma absorbs light
    • Thylakoids host light reactions; stroma hosts the Calvin cycle
    • All photosynthesis takes place in the outer envelope

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