# A student observing a cell under a light microscope notices several distinct organelles. Describe the function of the nucleus, mitochondria, and chloroplasts in a plant cell, and explain why animal cells lack one of these organelles.

> OCR GCSE Biology A: Gateway Science (J247) — B1.1 Cell structures · Describe · 4 marks

> A student is examining a palisade mesophyll cell from a leaf and an animal cell. They observe that the two cell types share some organelles but differ in others.

## Mark scheme (4 marks)

1. The nucleus contains the cell's genetic material and controls the activities of the cell.
2. Mitochondria are the site of aerobic respiration, releasing energy (as ATP) from glucose.
3. Chloroplasts are the site of photosynthesis; they contain chlorophyll which absorbs light energy.
4. Animal cells lack chloroplasts because they do not photosynthesise / they obtain energy from food rather than light.

## Key terms

- [nucleus](https://www.gradenine.co.uk/glossary/nucleus)
- [mitochondria](https://www.gradenine.co.uk/glossary/mitochondria)
- [chloroplasts](https://www.gradenine.co.uk/glossary/chloroplasts)

## Related

- [Revision notes for OCR GCSE Biology A: Gateway Science (J247)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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-observing-a-cell-under-51d3d02e) · Published by Druglandscape Ltd.