Lesson 4.4.1.2

4.4.1.2 Rate of photosynthesis Quiz: AQA Combined Science, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.4.1.2, Rate of photosynthesis: 20 multiple choice questions for the AQA GCSE Combined Science (8464), Unit 4: Bioenergetics, written with Revision Ninja.

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The 20 questions

  1. Which of these is a factor that affects the rate of photosynthesis?

    • Light intensity
    • Water pressure
    • Oxygen concentration
    • Nitrogen levels

  2. What is the primary function of chlorophyll in photosynthesis?

    • Absorb light energy
    • Produce water molecules
    • Release oxygen gas
    • Absorb carbon dioxide

  3. On a standard graph of photosynthesis rate, what is plotted on the y-axis?

    • Rate of photosynthesis
    • Temperature
    • Light intensity
    • Time elapsed

  4. What is commonly measured to find the rate of photosynthesis in pondweed?

    • Oxygen bubbles
    • Nitrogen gas
    • Water volume
    • Carbon dioxide bubbles

  5. What is defined as a factor in short supply that restricts the rate?

    • Inhibitor
    • Limiting factor
    • Catalyst
    • Independent variable

  6. What happens to the rate of photosynthesis when its sole limiting factor is increased?

    • It remains constant
    • It stops entirely
    • It decreases
    • It increases

  7. Which variable is typically changed on purpose in a pondweed photosynthesis experiment?

    • Volume of oxygen
    • Light intensity
    • Rate of reaction
    • Bubble count

  8. What is the general calculation used to determine rate?

    • Change plus time
    • Change multiplied by time
    • Time divided by change
    • Change divided by time

  9. If bubble production rises from 12 to 30 per minute at higher temperature, what is the conclusion?

    • Rate increased
    • Rate stayed constant
    • Rate stopped
    • Rate decreased

  10. A plant produces 48 cm3 of oxygen in 4 minutes. What is the rate?

    • 44 cm3 per minute
    • 192 cm3 per minute
    • 52 cm3 per minute
    • 12 cm3 per minute

  11. When the rate of photosynthesis levels off at high light intensity, what is usually responsible?

    • Complete darkness
    • Zero chlorophyll
    • Another limiting factor
    • No water present

  12. What happens to the rate of photosynthesis when a lamp is moved closer to pondweed?

    • It decreases
    • It increases
    • It stops
    • It reverses

  13. Why might greenhouse operators artificially increase carbon dioxide?

    • To increase crop yield
    • To reduce humidity
    • To prevent respiration
    • To decrease temperature

  14. Which environmental factor must be controlled during a light intensity photosynthesis practical?

    • Lamp distance
    • Bubble count
    • Light intensity
    • Temperature

  15. A plant has zero photosynthesis in the dark. Which factor is limiting?

    • Carbon dioxide concentration
    • Chlorophyll amount
    • Light intensity
    • Temperature

  16. In an experiment where carbon dioxide is changed and light is kept constant, what is the dependent variable?

    • Rate of photosynthesis
    • Temperature
    • Carbon dioxide concentration
    • Light intensity

  17. Why does the rate of photosynthesis drop sharply at very high temperatures?

    • Enzymes denature
    • Water boils
    • Chlorophyll freezes
    • Light is destroyed

  18. When a photosynthesis rate graph plateaus at increased carbon dioxide, what factor is usually limiting?

    • Chlorophyll
    • Carbon dioxide
    • Water availability
    • Light intensity

  19. In natural field environments, what determines which environmental factor limits photosynthesis?

    • Prevailing conditions
    • Plant species
    • Stomatal density
    • Leaf surface area

  20. Why should a student take repeat measurements in practicals?

    • Improves data reliability
    • Eliminates all errors
    • Reduces reaction time
    • Increases equipment cost

All AQA Combined Science quizzes