Lesson 5.5.1

5.5.1 Effect of temperature on enzyme activity 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 5.5.1, Effect of temperature on enzyme activity: 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 effect of increasing temperature on the rate of an enzyme-catalysed reaction below the optimum?

    • Molecules have more energy, so collisions are more frequent
    • The rate stays the same because enzymes are unaffected by temperature
    • The rate increases because the enzyme's active site becomes larger
    • The rate decreases because molecules move more slowly

  2. What happens to an enzyme when the temperature is raised far above its optimum?

    • It is converted into substrate molecules
    • It loses all its amino acids immediately
    • It becomes more active and the rate keeps rising
    • It denatures, changing its active site shape

  3. What is Q10 in the context of enzyme reactions?

    • The mass of substrate used in ten minutes
    • The temperature at which the enzyme is destroyed
    • Factor by which rate rises per 10 degree C
    • The number of enzyme molecules per litre of solution

  4. The rate of a reaction at 10 degrees C is 2 units per minute and at 20 degrees C is 8 units per minute. What is Q10?

    • 6
    • 4
    • 10
    • 2

  5. The rate at 15 degrees C is 3 and at 25 degrees C is 6 for a reaction. What is Q10?

    • 0.5
    • 3
    • 1
    • 2

  6. A reaction has Q10 = 2. The rate at 20 degrees C is 5 units. What is the rate at 30 degrees C?

    • 2.5 units
    • 7 units
    • 25 units
    • 10 units

  7. Why do many enzyme-catalysed reactions have a Q10 of about 2 to 3 over normal temperature ranges?

    • Temperature has no effect on collision frequency
    • Substrate molecules become smaller as temperature rises
    • Enzymes stop working entirely above 20 degrees C
    • Collisions become more frequent and energetic

  8. Which investigation design best tests the effect of temperature on enzyme activity?

    • Changing the colour of the water bath
    • Measuring rates at several temperatures, other factors fixed
    • Changing the enzyme concentration and the temperature at the same time
    • Measuring the rate at one temperature only

  9. A student uses a water bath at 40 degrees C and gets a slower rate than at 30 degrees C. What is the most likely explanation?

    • The enzyme is starting to denature at 40 degrees C, reducing its activity
    • Enzymes work faster at all temperatures with no limit
    • The enzyme's substrate becomes more concentrated at high temperature
    • The water bath has stopped heating the reaction

  10. Why does the rate of an enzyme reaction plateau at very high substrate concentrations?

    • Temperature falls as substrate concentration rises
    • Substrate molecules are destroyed at high concentration
    • All active sites are saturated, so enzyme level limits rate
    • Enzymes stop working when substrate is present in excess

  11. How might a Q10 value be used in an investigation of plant growth?

    • To measure how much rate rises per 10 degree C
    • To count the number of cells in a leaf
    • To measure the mass of the root system
    • To identify the colour of the leaves

  12. Which statement about temperature and microorganisms is correct?

    • Microorganisms are unaffected by temperature changes
    • Each species has an optimum; enzymes denature above it
    • All microorganisms have the same optimum temperature
    • Microorganisms grow fastest at the highest temperature possible

  13. A student measures rate at 20, 30, 40 and 50 degrees C. The rate peaks at 40 degrees C. What does this indicate?

    • The enzyme works best at 50 degrees C
    • The optimum is near 40 degrees C
    • The enzyme has no optimum temperature
    • The enzyme works best at 20 degrees C

  14. Why is the independent variable controlled in a temperature investigation with a water bath?

    • To make the dependent variable larger
    • So temperature is the only changing factor
    • To make the enzyme denature more quickly
    • To increase the substrate concentration

  15. Why is temperature important for plants, animals and microorganisms in relation to enzymes?

    • Enzymes control metabolism, so temperature matters
    • Enzymes are unaffected by temperature in all organisms
    • Temperature has no effect on metabolic reactions in living things
    • Enzymes are only found in animals, not plants or microorganisms

  16. A reaction's rate doubles for every 10 degree rise. What does this indicate about its Q10?

    • Q10 is 1
    • Q10 is 0.5
    • Q10 is 2
    • Q10 is 10

  17. What is the most likely reason for a Q10 near 1 in a reaction?

    • Substrate is in excess so temperature is irrelevant
    • The enzyme is denatured at all temperatures
    • The rate is doubling every ten degrees
    • Rate is barely affected by temperature

  18. A student says enzymes are destroyed by any temperature rise. What is the best evaluation?

    • Incorrect, because enzymes do not respond to temperature
    • Correct, because enzymes are only active at 0 degrees C
    • Incorrect, as rates rise to the optimum first
    • Correct, because all heat destroys enzymes

  19. Which method would best measure the effect of temperature on the development of seedlings?

    • Measuring seedling colour at one temperature only
    • Measuring the mass of soil without any seedlings
    • Counting seeds in one tray without temperature control
    • Measuring growth rate at several controlled temperatures

  20. Which data are needed to calculate a Q10 value for an enzyme-catalysed reaction?

    • The reaction rates at two temperatures that differ by 10 degrees C
    • The mass of the enzyme at a single temperature only
    • The pH of the solution at a single temperature only
    • The colour of the solution at the end of the reaction only

All Pearson Edexcel Biology A (Salters-Nuffield) quizzes