# A plant transports water and sugars through two separate transport systems. Describe how the structure of xylem vessels and phloem are each adapted to carry out their transport functions.

> OCR GCSE Biology A: Gateway Science (J247) — B2.2 The challenges of size · Describe · 4 marks

> Plants are multicellular organisms that require specialised transport tissues to move substances between different parts of the plant body.

## Mark scheme (4 marks)

1. Xylem vessels are lined with lignin, which provides strength and support (allowing water to be transported under tension without the vessel collapsing).
2. Xylem vessels are hollow/have no living cell contents, allowing water to flow freely through them.
3. Phloem sieve tubes are connected via their cytoplasms, allowing sugars/sucrose to move between cells.
4. Companion cells provide energy (via active transport) to support the movement of sugars through the phloem / for translocation.

## Key terms

- [xylem](https://www.gradenine.co.uk/glossary/xylem)
- [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 "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-plant-transports-water-and-sugars-aec4aaa5) · Published by Druglandscape Ltd.