Stages of mitosis. A. Prophase. Replicated chromosomes, consisting of two daughter strands …—© Merriam-Webster Inc.

Cell division, or reproduction, in which a cell gives rise to two genetically identical daughter cells. Strictly applied, the term describes the duplication and distribution of chromosomes. Prior to mitosis, each chromosome is replicated, producing two strands (chromatids) attached at a centromere. During mitosis, the membrane around the cell's nucleus dissolves and the chromatids of each chromosome are separated and pulled to each end of the cell. As the nuclear membrane re-forms around each set of chromosomes, the cytoplasm of the parent cell begins to divide to form two daughter cells. Following mitosis, the cell membrane pinches in to separate the daughter cells. Mitosis is essential to life because it provides new cells for growth and for replacement of worn-out cells. It may take minutes or hours, depending on the kind of cells and species of organisms. It is influenced by time of day, temperature, and chemicals. See also centromere, meiosis.

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