"This page [on Cell Division & Cancer] is brilliant as it helped
me to learn more about the disease and what to expect if it ever
occurs." When an egg has been fertilised, and thus becomes a
zygote, it undergoes mitosis, dividing to become two cells, then
four, then eight etc. In a human embryo, up to the eight-cell
stage all the cells are identical and have the potential to
become any kind of cell required by the body. These eight cells
are known as embryonic stem cells. Mitosis occurs in the natural
process of growth, but many plants and some animals also use
mitosis as a method of reproduction known as asexual
reproduction. The strawberry plant sends a runner out from the
main stem and, where this touches the ground, new plants develop
from buds on the runner. Spider plants regularly send out
drooping branches, which, if they touch the ground, will root
and produce new plants. The single-celled amoeba is one of a
small number of animals that reproduce asexually. The new plants
or animals produced are exact