Cellular division (Mitosis) is the biological process whereby a parent cell breaks itself into different parts called daughter cells.
This process is important because it helps to divide cells so that they can:
Cellular differentiation is the process of a cell going from one form to a more specialized cell.
A good example of this is the process of a fetus being formed from a single celled zygote.
Attached below is an image of cell differentiation and cellular division.