# Describe how osmosis causes a plant cell to become turgid when it is placed in a solution that is more dilute than the cell sap inside the vacuole.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.4 Movement of substances into and out of cells · Describe · 4 marks

## Mark scheme (4 marks)

1. The solution outside the cell is more dilute than the cell sap, so there is a higher concentration of water molecules outside the cell (than inside)
2. Water moves into the cell by osmosis across the partially permeable cell membrane
3. Water enters the vacuole, causing it to expand / the cell sap increases in volume
4. The vacuole pushes the cytoplasm against the cell wall, making the cell firm / turgid; the cell wall resists further expansion

## Key terms

- [osmosis](https://www.gradenine.co.uk/glossary/osmosis)
- [turgid](https://www.gradenine.co.uk/glossary/turgid)
- [vacuole](https://www.gradenine.co.uk/glossary/vacuole)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-how-osmosis-causes-a-plant-14631faf) · Published by Druglandscape Ltd.