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  2. Prophase - Wikipedia

    en.wikipedia.org/wiki/Prophase

    As it occurs after G2 of interphase, DNA has been already replicated when prophase begins. [1] Fluorescence microscope image of two mouse cell nuclei in prophase (scale bar is 5 μm). [2] Prophase (from Ancient Greek προ- 'before' and φάσις (phásis) 'appearance') is the first stage of cell division in both mitosis and meiosis.

  3. Zygotene - Wikipedia

    en.wikipedia.org/wiki/Zygotene

    Zygotene (from greek "paired threads" [1]) is the second stage of prophase I during meiosis, the specialized cell division that reduces the chromosome number by half to produce haploid gametes. It follows the Leptotene stage and is followed by Pachytene stage.

  4. Meiosis - Wikipedia

    en.wikipedia.org/wiki/Meiosis

    The identical sister chromatids have not yet condensed into the densely packaged chromosomes visible with the light microscope. This will take place during prophase I in meiosis. Growth 2 (G 2) phase: G 2 phase as seen before mitosis is not present in meiosis. Meiotic prophase corresponds most closely to the G 2 phase of the mitotic cell cycle.

  5. Chromosomal crossover - Wikipedia

    en.wikipedia.org/wiki/Chromosomal_crossover

    Crossing over occurs between prophase I and metaphase I and is the process where two homologous non-sister chromatids pair up with each other and exchange different segments of genetic material to form two recombinant chromosome sister chromatids. It can also happen during mitotic division, [1] which may

  6. Leptotene stage - Wikipedia

    en.wikipedia.org/wiki/Leptotene_stage

    The leptotene stage, also known as leptonema, is the first of five substages of prophase I during meiosis, ... [1]: 27 [2]: 353 ...

  7. Bivalent (genetics) - Wikipedia

    en.wikipedia.org/wiki/Bivalent_(genetics)

    The formation of a bivalent occurs during the first division of meiosis (in the zygotene stage of meiotic prophase 1). In most organisms, each replicated chromosome (composed of two identical sister chromatids [1] [2]) elicits formation of DNA double-strand breaks during the leptotene phase. [3]

  8. Resumption of meiosis - Wikipedia

    en.wikipedia.org/wiki/Resumption_of_meiosis

    At birth, meiosis arrests at the diplotene phase of prophase I. [7] Oocytes will remain in this state until the time of puberty. At the time of ovulation a surge of LH initiates the resumption of meiosis and oocytes enter the second cycle, which is known as oocyte maturation. Meiosis is then arrested again during metaphase 2 until fertilisation ...

  9. Cell division - Wikipedia

    en.wikipedia.org/wiki/Cell_division

    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. Cell division is the process by which a parent cell divides into two daughter cells. [1] Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing.