There are two processes by which cells divide: mitosis and meiosis. In mitosis, cells divide into two exact copies of the same cell. Meiosis is the method of dividing a cell into two sets of chromosomes to produce an egg and sperm for reproduction.
The cell cycle is the process that all cells must go through to stay alive, and it is made up of the stages of the division process.
Each cell contains genes, made up of 46 strands of DNA code known as chromosomes. The cell cycle begins when the chromosomes unravel so that each cell has two versions of each chromosome.
Once the DNA is copied, the chromosomes coil up into bundles. The edge of the cell's nucleus dissolves, and a temporary protein "scaffolding" is erected in its place. Chromosomes use this to help themselves line up in the center of the cell. Then, one copy of each chromosome moves to opposite ends of the cell. Finally, the cell narrows down the middle and divides.
The meiosis process works in a similar way, but instead of copying all 46 chromosomes, each of the two cells that are created only contain half, or 23, of the chromosomes. This generates the sperm and egg that are used in reproduction.