# Explain how the structure of a palisade mesophyll cell is adapted for its function in photosynthesis.

> IB DP Biology Standard Level (2023 syllabus) — B2.3 Cell specialisation · Explain · 4 marks

## Mark scheme (4 marks)

1. Palisade mesophyll cells contain a large number of chloroplasts, increasing the surface area/volume available for light absorption and the light-dependent reactions.
2. Chloroplasts can move/are positioned along the cell to optimise light capture or avoid photo-damage (chloroplast movement/orientation).
3. The elongated/columnar shape of palisade cells means they are arranged perpendicular to the leaf surface, reducing the path length for light to reach each chloroplast and packing more cells per unit area.
4. A large central vacuole pushes the chloroplasts to the periphery of the cell / towards the cell membrane, maximising exposure to CO₂ and light.

## Key terms

- [palisade mesophyll cell](https://www.gradenine.co.uk/glossary/palisade-mesophyll-cell)
- [photosynthesis](https://www.gradenine.co.uk/glossary/photosynthesis)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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-how-the-structure-of-a-dd6931d7) · Published by Druglandscape Ltd.