differentiation is the process that causes unspecialised cells to become specialised (have a specific function).
in animals, cells become specialised very early on in development.
unspecialised cells are called stem cells and are present in animal embryos - embryonic stem cells.
these can specialise into any cell (eg. muscle cell or white blood cell.
adult stem cells occur in babies, children and adults, wen the organism is fully developed.
adult stem cells can only specialise into a few cell types.
animal cells cannot re-differentiate.
Embryonic stem cells:
can be made to differentiate into any cell
can be used to treat patients with nerve damage (eg. paralysis) and diabetes (pancreas cells)
using stem cells damage or kill embryos
embryos cannot give consent
stem cell treatment many cause cancer
they can be contaminated with viruses (eg. HIV)