Embryonic stem cells and adult stem cells are both types of stem cell, but they differ in their ability to differentiate. Explain why embryonic stem cells are considered more useful than adult stem cells for treating a wide range of diseases, and describe where adult stem cells are found in the body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Scientists are researching how stem cells could be used to treat conditions such as diabetes and heart disease. They are comparing the potential uses of embryonic stem cells and adult stem cells.
Model answer (5 marks)
Embryonic stem cells are totipotent/pluripotent, so they can differentiate into any cell type in the body. This means they can be used to replace a wide range of damaged or diseased cells or tissues, making them highly useful for treating many conditions such as diabetes and heart disease. In contrast, adult stem cells are multipotent; they can only become a limited range of cell types, so their therapeutic potential is narrower.
Adult stem cells are found in various tissues, the most common example being bone marrow, where they give rise to blood cells.
Adult stem cells are found in various tissues, the most common example being bone marrow, where they give rise to blood cells.
Examiner tips
- Use the terms totipotent/pluripotent for embryonic and multipotent for adult; mention bone marrow as a key site.
- Explain the link between differentiation potential and therapeutic range.
- Keep the answer concise – 5 marks can be achieved with two short paragraphs.
Common mistakes
- Confusing totipotent with pluripotent or vice versa.
- Failing to name a specific location for adult stem cells, e.g. bone marrow.
- Not linking differentiation ability to the usefulness for disease treatment.
Mark scheme (5 marks)
- Embryonic stem cells can differentiate into any cell type (are totipotent/pluripotent)
- Adult stem cells can only differentiate into a limited range of cell types
- Because embryonic stem cells can become any cell type, they can be used to replace a wider variety of damaged or diseased cells/tissues
- Adult stem cells are found in bone marrow (as a named example)
- Cell differentiation is the process by which an undifferentiated stem cell becomes specialised for its function
Key terms in this question
embryonic stem cells · adult stem cells
Related
- All Edexcel A-Level Biology A: Salters-Nuffield (9BN0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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