# A farmer notices that tomato plants grown in a greenhouse produce more fruit when the greenhouse is heated and the carbon dioxide concentration inside is increased. Explain how increasing the temperature and increasing the carbon dioxide concentration inside the greenhouse each help to increase the rate of photosynthesis in the tomato plants.

> OCR A-Level Biology B — Advancing Biology (H422) — 4.1 Photosynthesis · Explain · 5 marks

> Tomato plants are grown commercially in heated greenhouses where carbon dioxide is pumped in artificially. Growers do this to maximise the yield of tomatoes produced.

## Mark scheme (5 marks)

1. Photosynthesis requires carbon dioxide (as a reactant)
2. Increasing carbon dioxide concentration increases the rate of photosynthesis (because more reactant is available)
3. Photosynthesis is an endothermic reaction that takes place in the chloroplasts and involves enzymes
4. Increasing temperature increases the rate of enzyme activity (up to the optimum temperature), so the rate of photosynthesis increases
5. More glucose is produced (by photosynthesis), providing more energy/materials for growth, leading to greater fruit yield

## Key terms

- [photosynthesis](https://www.gradenine.co.uk/glossary/photosynthesis)
- [carbon dioxide](https://www.gradenine.co.uk/glossary/carbon-dioxide)
- [rate of photosynthesis](https://www.gradenine.co.uk/glossary/rate-of-photosynthesis)

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](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-farmer-notices-that-tomato-plants-f8926a98) · Published by Druglandscape Ltd.