Stem Cells

This lesson covers stem cells, their types, uses and the ethical issues surrounding them, as required by the Edexcel GCSE Combined Science specification (1SC0). You need to understand the difference between embryonic and adult stem cells, describe their potential medical uses and discuss the ethical arguments.

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What Are Stem Cells?

Stem cells are undifferentiated (unspecialised) cells that have the ability to:

1. Divide by mitosis to produce more stem cells (self-renewal).
2. Differentiate into specialised cell types.

Stem cells are found in both animals and plants. They are important because they provide a source of new cells for growth, repair and, potentially, medical treatments.

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Types of Stem Cell

Embryonic Stem Cells

Embryonic stem cells are found in early-stage embryos (typically the blastocyst stage, about 4–5 days after fertilisation).

• They are pluripotent — they can differentiate into almost any type of cell in the body.
• This makes them extremely valuable for medical research and potential therapies.
• Embryos used for research are usually spare embryos from IVF (in vitro fertilisation) treatment.

Adult Stem Cells