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  2. Prophase - Wikipedia

    en.wikipedia.org/wiki/Prophase

    Prophase is the first stage of mitosis in animal cells, and the second stage of mitosis in plant cells. [10] At the start of prophase there are two identical copies of each chromosome in the cell due to replication in interphase. These copies are referred to as sister chromatids and are attached by DNA element called the centromere. [11]

  3. G1 phase - Wikipedia

    en.wikipedia.org/wiki/G1_phase

    Schematic karyogram of the human chromosomes, showing their usual state in the G 0 and G 1 phase of the cell cycle. At top center it also shows the chromosome 3 pair in metaphase (annotated as "Meta."), which takes place after having undergone DNA synthesis which occurs in the S phase (annotated as S) of the cell cycle.

  4. Mitosis - Wikipedia

    en.wikipedia.org/wiki/Mitosis

    Gene transcription ceases during prophase and does not resume until late anaphase to early G 1 phase. [40] [41] [42] The nucleolus also disappears during early prophase. [43] Close to the nucleus of an animal cell are structures called centrosomes, consisting of a pair of centrioles surrounded by a loose collection of proteins.

  5. Cell division - Wikipedia

    en.wikipedia.org/wiki/Cell_division

    Prophase is the first stage of division. The nuclear envelope begins to be broken down in this stage, long strands of chromatin condense to form shorter more visible strands called chromosomes, the nucleolus disappears, and the mitotic spindle begins to assemble from the two centrosomes. [ 21 ]

  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, the specialized cell division that reduces the chromosome number by half to produce haploid gametes in sexually reproducing organisms.

  7. 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.

  8. Chromosomal crossover - Wikipedia

    en.wikipedia.org/wiki/Chromosomal_crossover

    McClintock used the prophase and metaphase stages of mitosis to describe the morphology of corn's chromosomes, and later showed the first ever cytological demonstration of crossing over in meiosis. Working with student Harriet Creighton, McClintock also made significant contributions to the early understanding of codependency of linked genes.

  9. Synaptonemal complex - Wikipedia

    en.wikipedia.org/wiki/Synaptonemal_complex

    The synaptonemal complex is a tripartite structure consisting of two parallel lateral regions and a central element. This "tripartite structure" is seen during the pachytene stage of the first meiotic prophase, both in males and in females during gametogenesis.