Incell biology,mitosis(/maɪˈtoʊsɪs/) is a part of thecell cyclewhen replicatedchromosomesare separated into two new nuclei. Cell division gives rise to genetically identical cells in which the number of chromosomes is maintained. In general, mitosis (division of the nucleus) is preceded by the S stage ofinterphase(during which the DNA is replicated) and is often accompanied or followed bycytokinesis, which divides thecytoplasm,organellesandcell membraneinto two newcellscontaining roughly equal shares of these cellular components. Mitosis and cytokinesis together define themitotic(M)phaseof an animal cell cycle—thedivisionof the mother cell into two daughter cells genetically identical to each other.

The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages areprophase,prometaphase,metaphase,anaphase, andtelophase. During mitosis, the chromosomes, which have already duplicated, condense and attach to spindlefibersthat pull one copy of each chromosome to opposite sides of the cell. The result is two genetically identical daughter nuclei. The rest of the cell may then continue to divide by cytokinesis to produce two daughter cells. Producing three or more daughter cells instead of the normal two is a mitotic error called tripolar mitosis or multipolar mitosis (direct cell triplication / multiplication). Other errors during mitosis can induceapoptosis(programmed cell death) or causemutations. Certain types ofcancercan arise from such mutations.