# A student places a thin slice of fresh potato into a beaker of concentrated salt solution. After 30 minutes, the student notices that the potato slice has become soft and flexible. Explain why the potato slice became soft and flexible.

> Cambridge International IGCSE Biology (0610) — 3.1 Diffusion · Explain · 4 marks

## Mark scheme (4 marks)

1. Water moves out of the potato cells by osmosis
2. Water moves from the potato cells (higher water concentration / less concentrated) to the salt solution (lower water concentration / more concentrated), down the concentration gradient
3. The potato cells lose water and the cells become flaccid
4. Turgor pressure is reduced / lost, so the cells no longer push against the cell wall, causing the tissue to become soft and flexible

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-places-a-thin-slice-51c74b71) · Published by Druglandscape Ltd.