After growth from the zygote to the adult, cell division by mitosis allows for continual construction and repair of the organism. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself is produced by fusion of two gametes, each having been produced by meiotic cell division. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.įor simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. Prokaryotes ( bacteria and archaea) usually undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells, but there are alternative manners of division, such as budding, that have been observed.
Both are believed to be present in the last eukaryotic common ancestor. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. The different stages of mitosis all together define the mitotic ( M) phase of animal cell cycle-the division of the mother cell into two genetically identical daughter cells. In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA replication occurs) and is often followed by telophase and cytokinesis which divides the cytoplasm, organelles, and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained. In cell biology, mitosis ( /maɪˈtoʊsɪs/) is a part of the cell cycle, in which, replicated chromosomes are separated into two new nuclei. In eukaryotes, there are two distinct types of cell division: a vegetative division ( mitosis), producing daughter cells genetically identical to the parent cell, and a cell division that produces haploid gametes for sexual reproduction ( meiosis), reducing the number of chromosomes from two of each type in the diploid parent cell to one of each type in the daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. The cell cycle in eukaryotes: I = Interphase, M = Mitosis, G 0 = Gap 0, G 1 = Gap 1, G 2 = Gap 2, S = Synthesis, G 3 = Gap 3.Ĭell division is the process by which a parent cell divides into two daughter cells.
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