Mitosis makes new cells that are genetically identical to the parent cell, so it is used whenever an organism needs more of the same cells. It has three main uses.
- Growth: a multicellular organism starts as a single cell. Mitosis increases the number of cells, so the organism can grow.
- Repair: damaged or worn out cells are replaced by new cells made by mitosis, for example skin cells after a cut.
- Asexual reproduction: some organisms make offspring using only mitosis. Only one parent is needed and the offspring are genetically identical to it, so they are clones. Strawberry plants do this when they grow runners.
Because genes from two parents are not mixed, asexual reproduction gives offspring with very little variation. It is quick and needs no mate, but if conditions change, all the offspring are equally affected.