A patient has a condition that has destroyed the insulin-producing cells in their pancreas. Scientists are considering using either embryonic stem cells or adult stem cells to replace these damaged cells. Explain why embryonic stem cells would be more suitable than adult stem cells for producing the replacement pancreatic cells, and describe one ethical concern associated with using embryonic stem cells.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Stem cells are unspecialised cells that can divide and differentiate into specialised cell types. Two main sources of stem cells used in medical research are embryonic stem cells and adult stem cells.
Model answer (5 marks)
Embryonic stem cells are totipotent/pluripotent and can differentiate into any cell type, whereas adult stem cells are restricted to a limited range of cell types. Therefore embryonic stem cells can be directed to become insulin‑producing pancreatic cells, which adult stem cells cannot reliably generate. However, embryonic stem cells are isolated from early embryos, which must be destroyed in the process. This raises an ethical concern because some people believe the embryo has the potential to become a human life and should have the same moral status as a person.
Examiner tips
- State the totipotent/pluripotent nature of embryonic cells and the limited potency of adult cells. Explain how this difference allows directed differentiation into pancreatic cells. Mention the destruction of embryos and the moral status argument. Use exact terminology: totipotent, pluripotent, differentiation, ethical concern.
Common mistakes
- Confusing totipotent with pluripotent or vice versa. Failing to mention the destruction of embryos. Using vague terms like "stem cells" without specifying embryonic or adult. Not linking the ethical issue directly to embryo destruction.
Mark scheme (5 marks)
- Embryonic stem cells can differentiate into any cell type (they are totipotent/pluripotent)
- Adult stem cells can only differentiate into a limited range of cell types
- Therefore embryonic stem cells could be directed to differentiate into the specific insulin-producing pancreatic cells needed
- Embryonic stem cells are obtained from early embryos, which are destroyed in the process
- This raises ethical concerns because some people believe the embryo has the potential to become a human life / has the same moral status as a person
Key terms in this question
embryonic stem cells · adult stem cells
Related
- All Pearson Edexcel A-Level Biology A (9BI0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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