# Ethanol can be produced by fermentation. Describe the process of fermentation and explain why ethanol produced this way is considered a more sustainable fuel than petrol.

> AQA A-Level Chemistry (7405) — 3.3.11 Amines (A-Level only) · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Fermentation uses sugar/glucose (solution) as the starting material
2. Yeast is used / yeast acts as a catalyst / enzymes in yeast break down glucose
3. The process occurs without oxygen / anaerobically
4. Petrol is made from crude oil, which is a finite/non-renewable resource
5. Sugar/glucose used in fermentation comes from plants, which are renewable / can be regrown, making ethanol a more sustainable fuel

## Key terms

- [fermentation](https://www.gradenine.co.uk/glossary/fermentation)
- [ethanol](https://www.gradenine.co.uk/glossary/ethanol)

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/ethanol-can-be-produced-by-fermentation-bd95dbd0) · Published by Druglandscape Ltd.