A stem cell is an unspecialised cell with a remarkable ability to divide over and over and become differentiated into another type of cell, replacing damaged body tissue.
There are two tyes of stem cell used in the laboratory -
- embryonic stem cells - cells taken from embryos and which can differentiate into a number of different types of cell
- adult stem cells - a cell which is taken from adult tissue and which can differentiate into a cell type similar to that from which it was taken