A teenager is diagnosed with type 1 diabetes. Their pancreas no longer produces insulin. Scientists are investigating whether stem cells could be used to grow new insulin-producing cells for this patient. Explain how stem cells could be used to treat this patient, and why this treatment might be difficult to carry out.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Type 1 diabetes occurs when the immune system destroys the insulin-producing cells in the pancreas. Without insulin, blood glucose levels cannot be controlled, which can be life-threatening.
Model answer (5 marks)
Stem cells are undifferentiated cells that can divide and give rise to many different cell types.
Scientists can induce stem cells to differentiate into pancreatic beta cells that produce insulin.
The differentiated beta cells can then be transplanted into the patient’s pancreas to restore insulin production and regulate blood glucose.
However, the patient’s immune system may recognise the new cells as foreign and attack them, leading to rejection.
In addition, if embryonic stem cells are used, there are ethical concerns and difficulties in obtaining a sufficient supply of cells.
Scientists can induce stem cells to differentiate into pancreatic beta cells that produce insulin.
The differentiated beta cells can then be transplanted into the patient’s pancreas to restore insulin production and regulate blood glucose.
However, the patient’s immune system may recognise the new cells as foreign and attack them, leading to rejection.
In addition, if embryonic stem cells are used, there are ethical concerns and difficulties in obtaining a sufficient supply of cells.
Examiner tips
- Use the exact terms ‘undifferentiated’, ‘differentiate’, ‘beta cells’, ‘transplant’, ‘immune rejection’, and ‘ethical issues’.
- Show the logical sequence: stem cells → differentiation → transplantation → outcome, then list two difficulties.
- Keep each point brief to fit the 5‑mark limit.
Common mistakes
- Confusing stem cells with mature cells; not specifying beta cells. Omitting the immune rejection point or the ethical issue. Using vague language such as ‘new cells’ without identifying them as beta cells.
Mark scheme (5 marks)
- Stem cells are unspecialised / undifferentiated cells that can divide to produce many different cell types
- Stem cells can be made to differentiate into insulin-producing cells (beta cells / pancreatic cells)
- These new cells could then be transplanted into the patient's pancreas to restore insulin production / control blood glucose levels
- One difficulty is that the patient's immune system may reject the transplanted cells
- Another difficulty is the ethical issues surrounding the use of embryonic stem cells / difficulty obtaining sufficient stem cells
Key terms in this question
Related
- All OCR A-Level Biology B — Advancing Biology (H422) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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