What are stem cells?
Unspecialised cells that can develop into any other type of cell in an organism. They divide by mitosis.
What is differentiation?
The process by which a cell becomes specialised.
Define the term ‘totipotency’.
The ability of a stem cell to become any type of specialised cell in an organism, including extra-embryonic cells. They are only present in mammals after the first few divisions of an embryo. After this they become pluripotent.
Define the term ‘pluripotency’.
The ability of a stem cell to become any type of specialised cell in an organism, except extra-embryonic cells.
What is an extra-embryonic cell?
A cell that makes up part of the placenta or umbilical cord.
Where else are stem cells found?
- In some adult tissue, but they are less flexible than embryonic stem cells.
- In growing parts of plants (roots/stem)