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. What is the oxygen debt?

    • Money owed for gym fees
    • Extra oxygen used after exercise to clear lactate and restock
    • Holding your breath during a sprint
  2. Which releases more energy per glucose molecule?

    • Anaerobic respiration
    • Aerobic respiration
    • Both release exactly the same
  3. Yeast fermentation makes lactate, just like hard-working muscle.

    Circle one:   True   False

  4. Why does a sprinter breathe hard for minutes after finishing?

    • To cool the tongue
    • To repay the oxygen debt and clear lactate
    • To practise breathing
  5. Bread dough rises. Which process and gas are behind it?

    • Yeast fermentation making carbon dioxide
    • Muscle respiration making oxygen
    • Photosynthesis making sugar
  6. Which pair are the inputs of aerobic respiration?

    • Carbon dioxide and water
    • Glucose and oxygen
    • Lactate and ethanol
  7. A coach claims the debt is repaid by standing still and holding your breath. What is wrong?

    • Lactate clears itself instantly
    • Debts never get repaid
    • Repayment needs extra oxygen, so deep panting does the work
  8. Two runners sprint equally hard, but the fitter one makes less lactate. Why?

    • Fitter runners breathe less
    • Fitter muscles need no energy
    • Fitter bodies deliver oxygen faster, delaying the switch
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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. Extra oxygen used after exercise to clear lactate and restock · Hard minutes borrow energy that easy minutes repay with oxygen.
  2. Aerobic respiration · Oxygen pays hugely: about thirty ATP against two.
  3. False · Yeast makes ethanol and carbon dioxide, while muscle makes lactate.
  4. To repay the oxygen debt and clear lactate · Panting supplies the extra oxygen that clears lactate and restocks stores.
  5. Yeast fermentation making carbon dioxide · Yeast turns sugar into ethanol and carbon dioxide, which lifts the dough.
  6. Glucose and oxygen · Glucose plus oxygen burn fully into carbon dioxide, water and ATP.
  7. Repayment needs extra oxygen, so deep panting does the work · Holding breath starves the repayment that extra oxygen performs.
  8. Fitter bodies deliver oxygen faster, delaying the switch · Better delivery holds the aerobic path open longer.
Worksheet · LightMySky