A patient has been diagnosed with a blood disorder caused by faulty red blood cells. Doctors suggest using adult stem cells from bone marrow to treat the condition. Explain why adult stem cells from bone marrow could be used to treat this disorder, and suggest one limitation of using adult stem cells compared with embryonic stem cells for treating diseases.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Adult stem cells from bone marrow can differentiate into specialised blood cells, including red blood cells, so they can replace the faulty cells.
They divide by mitosis, producing large numbers of healthy cells to restore normal blood function.
However, adult stem cells are limited in their differentiation potential – they can only become a few related cell types.
In contrast, embryonic stem cells are pluripotent and can give rise to any cell type, allowing treatment of a wider range of disorders.
They divide by mitosis, producing large numbers of healthy cells to restore normal blood function.
However, adult stem cells are limited in their differentiation potential – they can only become a few related cell types.
In contrast, embryonic stem cells are pluripotent and can give rise to any cell type, allowing treatment of a wider range of disorders.
Examiner tips
- Use the word ‘differentiate’ and mention ‘mitosis’ to hit the key points.
- Show the limitation by contrasting adult with embryonic stem cells – this earns the extra mark.
- Keep the answer concise and use UK spelling.
Common mistakes
- Writing that adult stem cells can become any cell type (overstating their potential).
- Forgetting to mention mitosis as the mechanism for producing many cells.
Mark scheme (4 marks)
- Adult stem cells can differentiate / become specialised into different types of blood cell (including red blood cells)
- The stem cells divide by mitosis to produce large numbers of new, healthy blood cells
- Adult stem cells can only differentiate into a limited range of cell types (accept: they are not as versatile as embryonic stem cells)
- Embryonic stem cells can differentiate into any cell type, so they could treat a wider range of disorders / conditions than adult stem cells
Key terms in this question
adult stem cells · embryonic stem cells
Related
- Revision notes: Cell differentiation, growth and stem cells →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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