Question
A student sprints 100 m. Describe the physiological changes that occur in the body during and immediately after the sprint, and explain the role of anaerobic respiration. [6]
Mark scheme — level 3 (5–6): changes during + after + anaerobic with oxygen debt.
- During: heart rate increases → greater cardiac output → more O₂ delivered to muscles (B1)
- Breathing rate and depth (tidal volume) increase → more O₂ absorbed, CO₂ removed (B1)
- Muscle demand exceeds O₂ supply → anaerobic respiration occurs (B1)
- Anaerobic: glucose → lactic acid in muscles (B1)
- Lactic acid causes muscle fatigue / pain (B1)
- After sprint: continue to breathe rapidly to repay oxygen debt — O₂ used to oxidise lactic acid in liver (B1)
6 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.