# A student places a piece of potato into a concentrated salt solution and leaves it for 30 minutes. After 30 minutes, the potato piece has decreased in mass. Explain why the mass of the potato has decreased.

> Pearson Edexcel A-Level Biology A (9BI0) — 1.6 Membranes and transport · Explain · 5 marks

> A student places a piece of potato into a concentrated salt solution and leaves it for 30 minutes. After 30 minutes, the potato piece has decreased in mass.

## Mark scheme (5 marks)

1. Water moves out of the potato cells (into the salt solution)
2. By osmosis
3. The water potential / concentration of water is higher inside the potato cells than in the salt solution
4. Water moves through the partially permeable membrane (of the potato cell)
5. Loss of water from the cells causes the potato to lose mass

## Key terms

- [concentrated salt solution](https://www.gradenine.co.uk/glossary/concentrated-salt-solution)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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-places-a-piece-of-7d4f079b) · Published by Druglandscape Ltd.