# Explain how the structure of phloem is adapted to transport sucrose around a plant.

> OCR GCSE Biology A: Gateway Science (J247) — B2.1 Supplying the cell · Explain · 4 marks

> Plants produce sucrose by photosynthesis in their leaves. This sucrose must be transported to other parts of the plant, such as the roots and growing tips, where it is needed.

## Mark scheme (4 marks)

1. Sieve tubes have no nuclei, leaving more space for the flow of sucrose solution
2. Sieve tubes are connected via their cytoplasms, allowing sucrose to move continuously through the phloem
3. Companion cells provide energy (ATP) needed for translocation / active transport of sucrose
4. Translocation moves sucrose from a source (e.g. leaves) to a sink (e.g. roots / growing tips) where it is needed

## Key terms

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

## Related

- [Revision notes for OCR GCSE Biology A: Gateway Science (J247)](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-phloem-a8b783ee) · Published by Druglandscape Ltd.