Lesson T2.1.1

T2.1.1 Photosynthesis: reactants, products and word summary Quiz: KS3 Biology, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T2.1.1, Photosynthesis: reactants, products and word summary: 20 multiple choice questions for the KS3 Biology (National Curriculum), Unit 2: Material cycles and energy, written with Revision Ninja.

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The 20 questions

  1. What are the reactants in photosynthesis?

    • Oxygen and water
    • Carbon dioxide and water
    • Carbon dioxide and glucose
    • Glucose and oxygen

  2. What are the products of photosynthesis?

    • Carbon dioxide and water
    • Glucose and oxygen
    • Glucose and carbon dioxide
    • Oxygen and water

  3. Which word summary correctly describes photosynthesis?

    • Glucose + oxygen to carbon dioxide + water, in light and chlorophyll
    • Carbon dioxide + water to glucose + oxygen, in light
    • Carbon dioxide + oxygen to glucose + water, in light and using chlorophyll
    • Glucose + water to carbon dioxide + oxygen, in the dark

  4. Where does photosynthesis take place inside a plant cell?

    • In the cell wall, which gives support to the whole plant
    • In chloroplasts, which contain chlorophyll
    • In the nucleus, where the DNA of the cell is stored
    • In mitochondria, which release energy during respiration

  5. What energy source drives photosynthesis?

    • Energy released by mitochondria
    • Chemical energy stored in fats
    • Heat energy from the soil
    • Light energy from the Sun

  6. What is the job of chlorophyll in photosynthesis?

    • It stores glucose as starch
    • It reflects blue light into the air
    • It absorbs light energy
    • It absorbs carbon dioxide from the air

  7. Which gas do plants release during photosynthesis?

    • Hydrogen
    • Carbon dioxide
    • Nitrogen
    • Oxygen

  8. In what form is the glucose made in photosynthesis often stored?

    • Starch
    • Protein
    • Chlorophyll
    • Cellulose

  9. A pondweed is placed in bright light in water containing carbon dioxide. What gas is most likely released as bubbles?

    • Nitrogen
    • Oxygen
    • Carbon dioxide
    • Hydrogen

  10. A plant is kept in the dark for two days. Why does its starch level fall?

    • Starch is converted into chlorophyll pigment while it is dark
    • Starch dissolves in rainwater and washes out of the leaves slowly
    • Stored starch is used up for respiration, as no new glucose is made
    • Light turns starch into glucose and oxygen, so it is lost in darkness

  11. Where do plants take in the water used in photosynthesis?

    • Through the cuticle
    • Through the roots
    • Through the stomata
    • Through the petals

  12. Through what structures does carbon dioxide enter a leaf?

    • Stomata
    • Palisade cells
    • Xylem vessels
    • Phloem tubes

  13. What are the glucose products of photosynthesis used for?

    • Making oxygen in the stomata
    • Absorbing water into the roots
    • Lowering the temperature of the leaves
    • Growth, and as an energy store

  14. Why is water shown on the reactant side of the word summary?

    • Water cools the leaf during the reaction
    • Water is a product released from the leaves only
    • Water supplies hydrogen used to make glucose
    • Water is needed only to dissolve the oxygen gas

  15. Which evidence best shows that photosynthesis releases oxygen?

    • Gas bubbles from a pondweed in light relight a glowing splint
    • Leaves turning yellow in winter as the days become shorter
    • Bubbles of carbon dioxide rising in a sealed tank kept in the dark
    • Water droplets forming on the outside of a cold drinking glass

  16. Why is photosynthesis essential for almost all life on Earth?

    • It converts nitrogen gas from the air into food for many animals
    • It turns the Sun's light into heat that warms the whole planet's surface and air
    • It makes energy-storing food and releases the oxygen most life needs
    • It produces the clean water that all land animals drink to survive

  17. Which organisms other than plants can photosynthesise?

    • Mushrooms
    • Earthworms
    • Fungi
    • Algae

  18. In a greenhouse, which two conditions most directly increase the rate of photosynthesis?

    • Oxygen gas and nitrogen gas from the open air
    • Light and carbon dioxide
    • Glucose sugar and starch stored in the leaves
    • Water in the soil and minerals in the roots

  19. What do the arrows in a word summary show?

    • Gases diffusing back out into the air through the stomata
    • The direction of the reaction, from reactants to products
    • The path that sunlight takes through the leaf tissue
    • The movement of water through the xylem vessels of the plant

  20. Why does a plant still need glucose at night when it cannot photosynthesise?

    • Glucose is respired to release energy for life processes
    • Glucose stops chlorophyll from breaking down in the dark
    • Glucose blocks oxygen from leaving the stomata at night
    • Glucose must be turned into light energy for the leaves to glow

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