# A plant is kept in darkness for 48 hours and then moved into bright light. Explain why the plant must be kept in darkness before being placed in bright light, and describe what would happen to the starch content of the leaves during each of these two stages.

> Cambridge International IGCSE Biology (0610) — 6.1 Photosynthesis · Explain · 4 marks

## Mark scheme (4 marks)

1. The plant is kept in darkness to deplete / remove all existing starch from the leaves (destarch the plant).
2. In darkness, starch is broken down (into glucose) and used in respiration / for energy.
3. In bright light, photosynthesis occurs, producing glucose.
4. The glucose produced in photosynthesis is converted into starch for storage, so the starch content of the leaves increases in bright light.

## Key terms

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

## 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)
- [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-plant-is-kept-in-darkness-5ddc8086) · Published by Druglandscape Ltd.