A scientist is researching ways to grow replacement skin tissue in the laboratory for patients who have suffered severe burns. Explain why embryonic stem cells could be used to produce skin cells, and suggest one reason why adult stem cells from bone marrow might be less suitable for this purpose.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Severe burns can destroy large areas of skin tissue. Scientists are investigating the use of stem cells to grow replacement skin in the laboratory before transplanting it onto patients.
Model answer (5 marks)
Embryonic stem cells are undifferentiated and can become any cell type, including skin cells, because they are totipotent/pluripotent. When cultured in the laboratory they can be induced to differentiate into specialised epidermal cells, forming functional skin tissue.
Adult stem cells from bone marrow are limited to blood‑forming lineages and cannot give rise to skin cells. Therefore they are less suitable for producing replacement skin.
Adult stem cells from bone marrow are limited to blood‑forming lineages and cannot give rise to skin cells. Therefore they are less suitable for producing replacement skin.
Examiner tips
- Use the term ‘undifferentiated’ and ‘totipotent/pluripotent’ for embryonic cells. Show the link between differentiation and specialised skin cells. State the limited differentiation of bone‑marrow stem cells.
- common_mistakes
- :
- Calling embryonic cells ‘specialised’ instead of ‘undifferentiated’. Forgetting to mention that bone‑marrow cells cannot become skin cells. Using vague phrases like ‘can become many cells’ without specifying totipotency.
Mark scheme (5 marks)
- Embryonic stem cells are unspecialised / undifferentiated
- Embryonic stem cells can differentiate into any cell type (are totipotent/pluripotent / can become skin cells)
- Cell differentiation produces specialised skin cells from the embryonic stem cells
- Adult stem cells can only differentiate into a limited range of cell types
- Therefore bone marrow (adult) stem cells may not be able to differentiate into skin cells / are less likely to produce functional skin tissue
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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