B. Mitotic Phase: the phase in which the nucleus, followed by the cytoplasm, of the cell divide into two distinct daughter cells.
1. Mitosis – also called nuclear division Two complete sets of chromosomes are distributed into each of two nuclei
i) Prophase: Chromatids condense and pair up to become chromosomes Mitotic spindle forms and centrosomes move to opposite poles. Nucleolus disappears and the nuclear envelope breaks down. ii) Metaphase: Microtubules attach themselves and align centromeres a long the midline of the cell iii) Anaphase Centromeres split separating the two members of each chromatid pair, which are pulled toward opposite poles of the cell by the microtubules of the mitotic spindle. Once separated, the chromatids are termed Chromosomes. iv) Telophase The final stage of mitosis beginning after chromosomal movement stops. Two identical sets of chromosomes at opposite poles uncondensed (uncoil) and revert to the threadlike chromatin form. A nuclear envelope forms around each chromatin mass, and nucleoli reappear in the identical nuclei. The mitotic spindle is broken down.
2. Cytokinesis – also called cytoplasmic division The division of cytosol and organelles into two identical daughter cells Begins in late anaphase or early telophase
i) Cleavage furrow forms along the midline of plasma membrane ii) Contractile ring of actin filaments pinches the cell into two identical daughter cells along the cleavage furrow
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