# A student investigates osmosis using pieces of carrot. She places one piece of carrot into distilled water and another piece into a concentrated sugar solution for one hour. After one hour, the piece in distilled water feels firm, while the piece in the concentrated sugar solution feels soft and flexible. Explain why the two pieces of carrot feel different after one hour.

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

> Osmosis is the movement of water molecules across a partially permeable membrane from an area of higher water concentration to an area of lower water concentration.

## Mark scheme (5 marks)

1. Osmosis is the movement of water molecules across a partially permeable membrane
2. Water moves into the carrot in distilled water because the water concentration outside is higher than inside the carrot cells
3. Water entering the cells causes them to become turgid / swell, making the carrot firm
4. Water moves out of the carrot cells in concentrated sugar solution because the water concentration inside the carrot cells is higher than in the surrounding solution
5. Loss of water causes the carrot cells to become plasmolysed / lose turgor, making the carrot soft and flexible

## Key terms

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

## 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-investigates-osmosis-using-pieces-7169284b) · Published by Druglandscape Ltd.