Mitosis is necessary to replace dead cells, damaged cells, or cells that have short life spans. Meiosis is the process by which gametes sex cells are generated in organisms that reproduce sexually. Gametes are produced in male and female gonads and contain one-half the number of chromosomes as the original cell. New gene combinations are introduced in a population through the genetic recombination that occurs during meiosis. Thus, unlike the two genetically identical cells produced in mitosis, the meiotic cell cycle produces four cells that are genetically different.
Cell Division. Daughter Cell Number. Genetic Composition. Length of Prophase. Tetrad Formation. Chromosome Alignment in Metaphase. Chromosome Separation.
While the processes of mitosis and meiosis contain a number of differences, they are also similar in many ways. Both processes have a growth period called interphase , in which a cell replicates its genetic material and organelles in preparation for division. Both mitosis and meiosis involve phases: Prophase , Metaphase , Anaphase and Telophase. Although in meiosis, a cell goes through these cell cycle phases twice.
Both processes also involve the lining up of individual duplicated chromosomes, known as sister chromatids, along the metaphase plate. This happens in metaphase of mitosis and metaphase II of meiosis. In addition, both mitosis and meiosis involve the separation of sister chromatids and the formation of daughter chromosomes. This event occurs in anaphase of mitosis and anaphase II of meiosis.
Finally, both processes end with the division of the cytoplasm that produces individual cells. Actively scan device characteristics for identification. Use precise geolocation data. Most of these differences in the processes occur in meiosis I, which is a very different nuclear division than mitosis. In meiosis I, the homologous chromosome pairs become associated with each other, are bound together, experience chiasmata and crossover between sister chromatids, and line up along the metaphase plate in tetrads with spindle fibers from opposite spindle poles attached to each kinetochore of a homolog in a tetrad.
All of these events occur only in meiosis I, never in mitosis. Homologous chromosomes move to opposite poles during meiosis I so the number of sets of chromosomes in each nucleus-to-be is reduced from two to one. For this reason, meiosis I is referred to as a reduction division. There is no such reduction in ploidy level in mitosis. Meiosis II is much more analogous to a mitotic division. In this case, duplicated chromosomes only one set of them line up at the center of the cell with divided kinetochores attached to spindle fibers from opposite poles.
During anaphase II, as in mitotic anaphase, the kinetochores divide and one sister chromatid is pulled to one pole and the other sister chromatid is pulled to the other pole. If it were not for the fact that there had been crossovers, the two products of each meiosis II division would be identical as in mitosis; instead, they are different because there has always been at least one crossover per chromosome. Principles of Anatomy and Physiology. Improve this answer. It's Tortora "Principles of Anatomy and Physiology," 12th ed.
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