Mitosis and Meiosis
There are two types of cell division. Mitosis (in diploid cells) and meiosis (only in haploid cells, or gametes).
Mitosis
This type of cell division involves producing two cells with the diplod number of cells. The process with humans involves 23 pairs of chromosomes, so for this demonstration I will use a cell with just two pairs of chromosomes.
The chromosomes are copied exactly first, in a process called replication. These copies are called chromatids.
The chromatids line up along the equator of the cell and are attached to proteins called spindle fibres. These fibres begin to drag the chromatids apart. Taking parts to the opposite poles of the cell.
Now they are separated they can be called chromosomes and are surrounded by a nucleus. And two new daughter cells are created!
Meiosis
Meiosis must produce cells that have the haploid number of chromosomes. This process is sometimes called reduction division.
As with mitosis, the first stage is for the chromosomes to replicate. Now homologous pairs (both code for same characteristics) line up on the equator. Also the chratids will exchange bits of genetic information with each other. Increasing variation.
The homologous pairs separate and are moved to opposite poles of the cell. It now divides. These two daughter cells must divide again to form four gamete cells; each with a haploid number of chromosomes.