Stem cells can be used in medicine to treat a range of diseases. Explain why embryonic stem cells are considered more useful for medical treatments than adult stem cells, and describe one ethical issue associated with using embryonic stem cells.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Stem cell therapy is a relatively new area of medicine. Stem cells can be sourced from embryos or from bone marrow in adults.
Model answer (5 marks)
Embryonic stem cells are pluripotent – they can differentiate into any cell type in the body, whereas adult stem cells are multipotent and can only become a limited range of related cells. Because of this, embryonic stem cells can be used to replace a wider variety of damaged tissues and treat more diseases.
A major ethical issue is that harvesting embryonic stem cells destroys the embryo. This raises the question of whether the embryo should be regarded as a person and when life begins, leading to moral and legal controversy.
A major ethical issue is that harvesting embryonic stem cells destroys the embryo. This raises the question of whether the embryo should be regarded as a person and when life begins, leading to moral and legal controversy.
Examiner tips
- State the pluripotency of embryonic cells and restriction of adult cells; link to wider therapeutic potential; mention embryo destruction and personhood debate; keep answer concise and use exam terminology.
- Use clear, short sentences; avoid unnecessary words; include both points in a single paragraph to maximise marks.
Common mistakes
- Confusing pluripotent with totipotent; describing adult cells as totipotent; failing to mention the ethical issue of embryo destruction; writing too long or vague.
Mark scheme (5 marks)
- Embryonic stem cells can differentiate into any type of cell / are totipotent / are not restricted in the cell types they can become
- Adult stem cells can only differentiate into similar cell types / are more restricted in the cell types they can become
- This means embryonic stem cells can be used to treat a wider variety / larger range of diseases or damaged tissues
- Embryos are destroyed when stem cells are harvested from them
- This raises the ethical question of whether the embryo should be considered a person / when life begins
Key terms in this question
stem cells · embryonic stem cell · adult stem cell
Related
- All WJEC A-Level Biology (Wales) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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