# Explain why a flowering plant needs both photosynthesis and respiration to occur simultaneously during the day, with reference to the gases involved in gas exchange.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.8 Gas exchange: flowering plants · Explain · 4 marks

> A flowering plant is kept in bright light for several hours during the day. Gas exchange occurs through the stomata on the leaf surface.

## Mark scheme (4 marks)

1. Photosynthesis uses / takes in carbon dioxide (from the air / surroundings)
2. Photosynthesis releases / produces oxygen (which diffuses out through stomata)
3. Respiration uses / requires oxygen (to release energy from glucose)
4. Respiration produces / releases carbon dioxide, which can be used directly in photosynthesis / so gas exchange involves a net uptake of carbon dioxide in bright light

## Key terms

- [photosynthesis](https://www.gradenine.co.uk/glossary/photosynthesis)
- [respiration](https://www.gradenine.co.uk/glossary/respiration)
- [gas exchange](https://www.gradenine.co.uk/glossary/gas-exchange)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](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/explain-why-a-flowering-plant-needs-27e31178) · Published by Druglandscape Ltd.