# A student cuts their finger during a sports lesson and notices the wound feels warm. Explain how anaerobic respiration in the muscle cells during exercise contributes to changes in the body, and describe one difference between anaerobic and aerobic respiration in animal cells.

> OCR GCSE Biology A: Gateway Science (J247) — B1.3 Respiration · Explain · 4 marks

> During intense exercise, muscle cells may not receive enough oxygen to meet their energy demands. They switch from aerobic respiration to anaerobic respiration. Cellular respiration is a continuously occurring chemical process that releases energy from the breakdown of organic compounds such as glucose.

## Mark scheme (4 marks)

1. Anaerobic respiration occurs when there is an insufficient/inadequate supply of oxygen (oxygen debt)
2. Anaerobic respiration in animal cells produces lactic acid (from glucose)
3. Aerobic respiration uses/requires oxygen whereas anaerobic respiration does not use oxygen
4. Aerobic respiration releases more energy (from glucose) than anaerobic respiration

## Key terms

- [anaerobic respiration](https://www.gradenine.co.uk/glossary/anaerobic-respiration)
- [aerobic respiration](https://www.gradenine.co.uk/glossary/aerobic-respiration)

## Related

- [Revision notes for OCR GCSE Biology A: Gateway Science (J247)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-cuts-their-finger-during-84233051) · Published by Druglandscape Ltd.