# State four structural features of red blood cells and, for each feature, explain how it helps in the transport of oxygen.

> Cambridge International IGCSE Biology (0610) — 9.4 Blood · Explain · 4 marks

## Mark scheme (4 marks)

1. Red blood cells contain haemoglobin, which binds to oxygen for transport.
2. Red blood cells are biconcave in shape, giving a large surface area relative to volume, increasing the rate of diffusion of oxygen into and out of the cell.
3. Red blood cells have no nucleus (are anucleate), leaving more space for haemoglobin so more oxygen can be carried.
4. Red blood cells are small and flexible, allowing them to pass through narrow capillaries so oxygen can be delivered to all tissues.

## Key terms

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

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Source: [GradeNine](https://www.gradenine.co.uk/q/state-four-structural-features-of-red-78a0fdaa) · Published by Druglandscape Ltd.