# A doctor explains to a patient that red blood cells are highly specialised cells. Describe the features of a red blood cell that make it well adapted for carrying oxygen around the body, and explain how each feature helps it carry out this function.

> OCR A-Level Biology B — Advancing Biology (H422) — 2.2 Biological molecules including biochemistry · Describe · 5 marks

> Red blood cells are produced in the bone marrow and released into the blood, where they transport oxygen to respiring cells throughout the body.

## Mark scheme (5 marks)

1. Red blood cells have a biconcave shape
2. The biconcave shape increases the surface area (for oxygen absorption / diffusion of oxygen into the cell)
3. Red blood cells have no nucleus
4. Having no nucleus leaves more space / room for haemoglobin (so more oxygen can be carried)
5. Red blood cells contain haemoglobin, which binds to / carries oxygen

## Key terms

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

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](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-doctor-explains-to-a-patient-c4069a40) · Published by Druglandscape Ltd.