Lesson T2.2.3

T2.2.3 Anaerobic respiration and fermentation Quiz: KS3 Biology, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T2.2.3, Anaerobic respiration and fermentation: 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 is fermentation?

    • Digestion of fats in the small intestine
    • Aerobic respiration in plant leaves that happens only during the night
    • Anaerobic respiration in yeast, producing ethanol and carbon dioxide
    • Photosynthesis that takes place in dark conditions inside the leaves

  2. Which word summary describes anaerobic respiration in humans?

    • Glucose to lactic acid, releasing some energy
    • Glucose to ethanol and carbon dioxide, releasing energy
    • Lactic acid to glucose + oxygen
    • Glucose + oxygen to carbon dioxide + water

  3. Which word summary describes yeast fermentation?

    • Glucose to ethanol and carbon dioxide
    • Glucose to lactic acid
    • Ethanol to glucose + oxygen
    • Glucose + oxygen to water + carbon dioxide

  4. Why does lactic acid build up in muscles?

    • Oxygen supply cannot keep up with muscle demand
    • The heart stops pumping blood around the body for a while
    • Muscles release too much oxygen during long periods of exercise
    • Glucose is turned into oxygen gas in the muscle cells

  5. Why does a person keep breathing heavily after exercise?

    • To store oxygen in the muscles for the next time they run
    • To repay the oxygen debt and break down the lactic acid
    • To release more glucose from the liver
    • To cool the body by losing water vapour through the skin

  6. Which micro-organism is used to make bread and alcohol through fermentation?

    • Yeast
    • Penicillium
    • Paramecium
    • Amoeba

  7. Why is anaerobic respiration useful to yeast in beer making?

    • It produces ethanol
    • It produces lactic acid which thickens the drink
    • It makes glucose which sweetens the drink
    • It produces oxygen which makes the drink fizz

  8. Why is anaerobic respiration only a short-term option for animals?

    • It produces too much oxygen in the body's blood
    • It uses up all the stored water
    • Lactic acid builds up and causes fatigue
    • It stops once the lungs fill with air during the breath

  9. Where does anaerobic respiration take place in humans?

    • In the stomata on the underside of the plant's leaves
    • In the stomach lining during the digestion of a meal
    • In the xylem vessels that carry water up the plant
    • In muscle cells during strenuous exercise

  10. Which product of yeast fermentation makes bread dough rise?

    • Lactic acid, which is made by yeast in the dough
    • Water, which is made when the flour is mixed in
    • Ethanol, which evaporates during baking in the oven
    • Carbon dioxide

  11. Which factor makes muscle fatigue more likely?

    • Lactic acid building up faster than it can be removed
    • Glucose being stored as starch in the muscle cells at rest
    • Nerves sending signals too slowly
    • Too much oxygen in the muscle cells during hard exercise

  12. Which statement compares energy release correctly?

    • The same energy per glucose is released by both types
    • No energy is released by anaerobic respiration
    • More energy per glucose molecule is released in anaerobic respiration
    • Anaerobic respiration releases less energy per glucose

  13. What are the reactants in yeast fermentation?

    • Glucose only
    • Ethanol and oxygen
    • Glucose and oxygen
    • Lactic acid and water

  14. Why is fermentation described as anaerobic respiration?

    • It uses oxygen but releases no energy at all from glucose
    • It releases energy from light without using glucose
    • It uses carbon dioxide instead of oxygen to release energy
    • It releases energy from glucose without using oxygen

  15. A runner's muscles run short of oxygen. Which change in breathing helps recovery?

    • Stopping blood flow to the legs for a while
    • Holding the breath for long periods to store oxygen in the blood
    • Breathing faster to supply oxygen for lactic acid
    • Cooling the muscles to stop lactic acid forming

  16. Why does the rate of yeast fermentation eventually slow in a sugar solution?

    • High ethanol levels poison the yeast
    • Yeast needs more lactic acid to survive
    • Yeast runs out of light
    • Yeast starts producing oxygen

  17. What is the advantage of anaerobic respiration for an organism?

    • It produces oxygen for other cells in the same organism
    • It releases more energy than aerobic respiration does in cells
    • It produces water that cools the body during exercise
    • It releases energy quickly when oxygen is in short supply

  18. Why do cells that run out of oxygen not stop releasing energy at once?

    • Glucose is turned into oxygen gas inside the cell itself
    • Cells store oxygen for emergencies in the nucleus of the cell
    • Respiration stops and cells rely on light instead of food
    • Anaerobic respiration keeps some energy flowing briefly

  19. Which is a difference between lactic acid fermentation and yeast fermentation?

    • Muscles make lactic acid; yeast makes ethanol and carbon dioxide
    • Muscles make ethanol, while yeast makes lactic acid as its product
    • Both make ethanol and oxygen gas as their main products
    • Both make lactic acid and water

  20. Why does yeast need sugar to produce carbon dioxide?

    • Sugar is stored by yeast as lactic acid in its cells
    • Sugar provides oxygen for respiration in the yeast cells
    • Sugar is the glucose it breaks down for energy
    • Sugar cools the yeast so that it can respire without heat damage

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