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  2. Cell division - Wikipedia

    en.wikipedia.org/wiki/Cell_division

    These chromosomes have already been replicated and have two sister chromatids which are then separated during the second division of meiosis. [4] Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor.

  3. Meiosis - Wikipedia

    en.wikipedia.org/wiki/Meiosis

    Meiosis (/ m aɪ ˈ oʊ s ɪ s / ⓘ; from Ancient Greek μείωσις (meíōsis) 'lessening', (since it is a reductional division) [1] [2] is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells.

  4. Spermatogenesis - Wikipedia

    en.wikipedia.org/wiki/Spermatogenesis

    The primary spermatocyte divides meiotically (Meiosis I) into two secondary spermatocytes; each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into spermatozoa (sperm) by the process of spermiogenesis. These develop into mature spermatozoa, also known as sperm cells. [2]

  5. Nondisjunction - Wikipedia

    en.wikipedia.org/wiki/Nondisjunction

    In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and meiosis II are specialized forms of cell division occurring during generation of gametes (eggs and sperm) for sexual reproduction, mitosis is the form of cell division used by all other cells ...

  6. Cell cycle - Wikipedia

    en.wikipedia.org/wiki/Cell_cycle

    The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.

  7. Chromosomal crossover - Wikipedia

    en.wikipedia.org/wiki/Chromosomal_crossover

    It can also happen during mitotic division, [1] which may result in loss of heterozygosity. Crossing over is important for the normal segregation of chromosomes during meiosis. [ 2 ] Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the ...

  8. Origin and function of meiosis - Wikipedia

    en.wikipedia.org/wiki/Origin_and_function_of_meiosis

    Meiosis generates genetic variation in the diploid cell, in part by the exchange of genetic information between the pairs of chromosomes after they align (recombination). Thus, on this view, [28] an advantage of meiosis is that it facilitates the generation of genomic diversity among progeny, allowing adaptation to adverse changes in the ...

  9. Sister chromatids - Wikipedia

    en.wikipedia.org/wiki/Sister_chromatids

    A pair of sister chromatids is called a dyad. A full set of sister chromatids is created during the synthesis phase of interphase, when all the chromosomes in a cell are replicated. The two sister chromatids are separated from each other into two different cells during mitosis or during the second division of meiosis.