Cell division is the basis of life itself; it is how animals grow and reproduce. When cells divide, two daughter cells are produced from one mother cell. Each new cell has exactly the same genetic material (DNA) as the cell that produced it.

Cellular division has three main functions: (1) the reproduction of an entire unicellular organism, (2) the growth and repair of tissues in multicellular animals, and (3) the formation of gametes (eggs and sperm) for sexual reproduction in multicellular animals. The process of mitosis produces identical cells for the first two functions listed above; the process of meiosis forms gametes.

Cellular division has two steps. First, the genome is divided up inside the nucleus by either mitosis or meiosis. Second, the cytoplasm (the rest of the content of the cell) is divided. The cell is actually split in two in a process called cytokinesis, in which the...