# A yeast cell is placed in a sealed container with a small amount of glucose solution. Explain what happens to the rate of anaerobic respiration in the yeast cell over time as the glucose is used up, and describe what waste product accumulates inside the container.

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

> Yeast cells can respire both aerobically and anaerobically depending on the availability of oxygen. In a sealed container, the yeast quickly uses up any available oxygen.

## Mark scheme (4 marks)

1. Yeast carries out anaerobic respiration (when oxygen runs out / in the absence of oxygen)
2. Glucose is broken down / used as a reactant in anaerobic respiration
3. As glucose is used up / becomes a limiting factor, the rate of anaerobic respiration decreases
4. Ethanol (and carbon dioxide) accumulates as the waste product of anaerobic respiration in yeast

## Key terms

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

## 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-yeast-cell-is-placed-in-480b1898) · Published by Druglandscape Ltd.