Mitosis is the duplication of a cell's chromosomes during binary fission. Mitosis has five stages, which are the following: interphase, prophase, metaphase, anaphase, and telophase.
The first stage is interphase. During this stage the cell grows and does its normal thing. When it gets too big to feed itself it knows that it is time to start mitosis. Then, its DNA replicates.
The second stage is prophase. The first thing that happens in this stage is that the chromosomes become short and thick. Then, the nuclear membrane disappears. Finally the chromosomes duplicate so there are twice as many chromosomes in the cell.
The third stage is metaphase. In this stage the chromosomes first line up in the middle of the cell. Secondly, asters develop at both sides of the cell. Attached to the asters are long threadlike structures called fibrils. These fibrils attach to the centromeres of each chromosome.
The fourth stage of this process is called anaphase.
First, the fibrils contract, pulling the chromosomes apart toward the asters. Lastly, the chromosomes collect around the asters.
The fifth and final stage of mitosis is telophase. During this phase the nuclear membrane reforms around each set of chromosomes. Finally the cell pinches in half forming two daughter cells.
This is the wonder we call mitosis.