# A patient is diagnosed with leukaemia, a cancer of the blood. Doctors suggest a bone marrow transplant as a treatment. Bone marrow contains stem cells. Describe what stem cells are and explain how a bone marrow transplant could be used to treat leukaemia.

> OCR A-Level Biology B — Advancing Biology (H422) — 3.1 Cell division and stem cells · Describe and Explain · 5 marks

> Leukaemia is a type of cancer in which the bone marrow produces abnormal white blood cells that cannot fight infection properly. A bone marrow transplant involves replacing the patient's damaged bone marrow with healthy bone marrow from a donor.

## Mark scheme (5 marks)

1. Stem cells are unspecialised / undifferentiated cells
2. Stem cells can differentiate into many different cell types / any type of cell
3. Stem cells can divide (by mitosis) to produce more cells
4. The donor stem cells in the bone marrow can differentiate into normal / healthy white blood cells
5. This replaces the abnormal / cancerous white blood cells so the patient can fight infection

## Key terms

- [stem cells](https://www.gradenine.co.uk/glossary/stem-cells)
- [bone marrow](https://www.gradenine.co.uk/glossary/bone-marrow)

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/a-patient-is-diagnosed-with-leukaemia-bf67ad22) · Published by Druglandscape Ltd.