What Are Stem Cells?
An undifferentiated cell that has the capacity to divide indefinitely by mitosis and to differentiate into one or more specialized cell types.
Stem cells are fundamental to life — they drive growth and development in embryos, and they maintain and repair tissues throughout an organism's lifespan. Not all stem cells are equal, however. Their potency — the range of cell types they can give rise to — varies significantly.
Biologists classify stem cells into three main categories based on this potency:
- Totipotent — can become any cell type, including extra-embryonic tissues
- Pluripotent — can become any cell type of the body, but not extra-embryonic tissues
- Multipotent — can become a limited range of related cell types within a specific tissue
Understanding the differences between these categories is essential for both developmental biology and the growing field of regenerative medicine.
The prefixes help you remember the hierarchy: toti- (Latin for "all/whole"), pluri- (Latin for "many"), multi- (Latin for "several"). Potency decreases from totipotent → pluripotent → multipotent.