# Red blood cells and platelets are two components of blood. Describe how the structure of red blood cells and platelets is adapted to their functions in transporting substances and repairing damage in the human body.

> Eduqas A-Level Biology — 2.3 Adaptations for transport in plants and animals · Describe · 5 marks

## Mark scheme (5 marks)

1. Red blood cells contain haemoglobin which carries/binds oxygen
2. Red blood cells have a biconcave shape which increases surface area for gaseous exchange
3. Red blood cells have no nucleus, allowing more space/volume for haemoglobin
4. Platelets are cell fragments that stick to a broken/damaged vessel wall and clump together to block the cut
5. Clumping of platelets forms a scab/clot which prevents pathogens entering and allows the vessel to heal

## Key terms

- [platelets](https://www.gradenine.co.uk/glossary/platelets)
- [red blood cells](https://www.gradenine.co.uk/glossary/red-blood-cells)

## Related

- [Revision notes for Eduqas A-Level Biology](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/red-blood-cells-and-platelets-are-66bad3b7) · Published by Druglandscape Ltd.