Respiration: Energy Yield, Oxygen Debt and Fermentation · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Why sprinters keep panting

Science · Organisms & Life Processes · ages 15-16
Name ______________________   Date ____________

  1. In exercise recovery, what does repaying an oxygen debt refer to?

    • Using extra oxygen above the resting level
    • Replacing all the glucose used during exercise
    • Keeping oxygen use below the resting level

  2. Which pathway produces more ATP from one glucose molecule in human cells?

    • Glycolysis followed by lactate formation
    • Aerobic respiration
    • Both pathways produce equal amounts

  3. Yeast fermentation makes lactate, just like the pathway used in hard-working muscle.

    Circle one:   True   False

  4. A muscle produces lactate during a sprint. Which statement about its ATP supply is correct?

    • Lactate production means aerobic respiration has stopped entirely
    • Aerobic respiration can continue while glycolysis supplies extra ATP
    • Glycolysis needs oxygen before it can supply ATP during the sprint

  5. Which process produces the gas bubbles that expand bread dough?

    • Yeast fermentation releasing ethanol vapour
    • Muscle lactate formation releasing oxygen
    • Yeast fermentation releasing carbon dioxide

  6. Which pair belongs on the input side of the aerobic respiration word equation?

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

  7. A student says all lactate made during exercise must be excreted as useless waste. Which statement corrects this?

    • All lactate remains in muscle permanently and cannot be used by other tissues
    • All lactate becomes ethanol and carbon dioxide during recovery in human muscle
    • Some lactate is oxidised as fuel; some is converted to glucose in the liver

  8. In a model, glucose is a runner's only fuel. After endurance training, the same workload needs the same ATP per minute but less glucose. Which change in pathway use could explain this?

    • A greater aerobic contribution gives more ATP per glucose
    • A greater lactate-pathway contribution gives more ATP per glucose
    • An unchanged pathway mix gives more ATP because glucose is used faster
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Why sprinters keep panting W1-mt_mvnCjThdTH-s1

  1. Using extra oxygen above the resting level · The term refers to extra oxygen use during recovery, not to lactate itself or the amount of glucose used.
  2. Aerobic respiration · Aerobic respiration usually yields about 30 ATP per glucose, compared with a net 2 through glycolysis followed by lactate formation.
  3. False · Yeast fermentation makes ethanol and carbon dioxide. The muscle pathway makes lactate.
  4. Aerobic respiration can continue while glycolysis supplies extra ATP · The pathways can contribute at the same time. Lactate production does not show that aerobic respiration has stopped.
  5. Yeast fermentation releasing carbon dioxide · Yeast fermentation produces carbon dioxide. Bubbles of this gas expand the dough.
  6. Glucose and oxygen · The word equation starts with glucose and oxygen and ends with carbon dioxide and water.
  7. Some lactate is oxidised as fuel; some is converted to glucose in the liver · Lactate can be used as fuel or converted to glucose. It is not all excreted as useless waste.
  8. A greater aerobic contribution gives more ATP per glucose · Aerobic respiration yields more ATP per glucose. A greater aerobic contribution can meet the same ATP demand using less glucose.
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