A eukaryotic cell typically has a great deal of genetic material. For example, if the DNA of a human cell were uncoiled and lined end-to-end, it would extend approximately two meters! This genetic material is replicated before cell division and then must be divided equally between daughter cells. In mitosis, which is the division of the nucleus, the chromosomes condense into bodies small enough to travel efficiently in the cell, and then the chromosomes play out an intricate choreography. At the end of mitosis, the chromosomes have been partitioned into two new nuclei. These nuclei become part of daughter cells that are genetically identical to each other and to the parent cell.
The accompanying animation depicts the movements of chromosomes in mitosis, the dissolution and reformation of nuclear membranes, the formation of the mitotic spindle, and the division of the cytoplasm (called cytokinesis) that results in two new daughter cells.
Although mitosis is a continuous event, biologists typically divide it into a series of phases. The phases of mitosis are the following:
Cytokinesis, the division of the cytoplasm, follows mitosis. In this part of the cell division cycle, a contractile ring pinches the cell at its midplane. The two daughter cells that form are each genetically identical to the parent cell.
Textbook Reference: Concept 7.2 Both Binary Fission and Mitosis Produce Genetically Identical Cells