# Explain why anaerobic cell respiration produces a much smaller yield of ATP per glucose molecule than aerobic cell respiration.

> IB DP Biology Standard Level (2023 syllabus) — C1.2 Cell respiration · Explain · 4 marks

## Mark scheme (4 marks)

1. Aerobic respiration fully oxidises glucose / breaks glucose down completely to carbon dioxide and water, releasing more energy for ATP synthesis.
2. Anaerobic respiration only partially oxidises glucose, producing lactate (in animals/bacteria) or ethanol and carbon dioxide (in yeast), so much of the chemical energy remains in these products.
3. Aerobic respiration uses the electron transport chain / oxidative phosphorylation on the inner mitochondrial membrane to generate the majority of ATP, which is absent in anaerobic respiration.
4. Anaerobic respiration yields only 2 ATP per glucose (from glycolysis alone), whereas aerobic respiration yields approximately 30–32 ATP per glucose.

## Key terms

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

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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/explain-why-anaerobic-cell-respiration-produces-f45868ce) · Published by Druglandscape Ltd.