Stem CellsEdexcel GCSE Biology: Revision notes
Section 1
What Are Stem Cells?
A stem cell is an undifferentiated cell that can divide and differentiate into one or more specialised cell types. Sources: embryonic stem cells, adult (animal) stem cells, meristem cells in plants.
Always use the term 'differentiate', not 'turn into'.
Section 2
Embryonic Stem Cells
Found in early embryos; pluripotent — can differentiate into any cell type, making them very useful for medical research.
Section 3
Stem Cells in Animals
Found in tissues like bone marrow; can only differentiate into a limited number of cell types (e.g. blood cells). Main role: repair/replacement.
Contrast embryonic (any cell type) with adult (limited types) explicitly.
Section 4
Meristems in Plants
Found at root and shoot tips; can differentiate into any plant cell type for the plant's whole life, enabling growth and cloning via cuttings.
A meristem is like a permanent stem cell factory in plants.
Section 5
Benefits and Risks of Stem Cells in Medicine
Benefits: growing replacement tissues/organs, treating blood disorders. Risks: viral infection transfer, transplant rejection, ethical objections over embryo destruction.
Evaluate questions need both a benefit AND a risk plus a conclusion.
Must Know
- Embryonic stem cells: pluripotent, any cell type.
- Adult stem cells: limited cell types.
- Meristems: any plant cell, whole life, enable cloning.
- Benefits: treat disease/injury; Risks: infection, rejection, ethics.
That's the notes covered.
Carry on to the next subtopic.