# A student grows some algae in a sealed, transparent container filled with water. The algae carry out photosynthesis. Explain how the algae use the raw materials available to them to produce glucose during photosynthesis.

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

> Algae are aquatic producers that photosynthesise using dissolved carbon dioxide and water. A student places algae in a sealed, transparent container and exposes it to sunlight. Over several hours, the student notices that oxygen bubbles form inside the container.

## Mark scheme (5 marks)

1. Photosynthesis uses carbon dioxide and water as raw materials
2. Light energy is required / absorbed for photosynthesis to occur
3. The reaction takes place in the chloroplasts
4. Glucose is produced as a product of photosynthesis
5. Oxygen is also released as a product, which explains the bubble formation

## Key terms

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

## 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-student-grows-some-algae-in-1c42c10d) · Published by Druglandscape Ltd.