BIOL 1000 Chapter Notes - Chapter 0: Sister Chromatids, Spindle Apparatus, Cohesin
14 Jun 2019
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Chromosomes condense (with the help of condensin proteins) and become visible inside nucleus. Each chromosome is in duplicate, consisting of two sister chromosomes held together by cohesins. Cytoskeleton rearranges, asters around each pair of centrioles. Centrosomes separate moving to opposite ends outside the nucleus, creating bipolar cell and beginning of spindle. Chromosomes released into cytoplasm, make connections with microtubules at the kinetochores and begin to move within the spindle. Chromosomes come to rest at the metaphase plate. Each sister chromatid in each chromosome faces and is connected to opposite poles. Cohesin is broken down by enzymes, so sister chromatids can separate once they separate they are technically each a chromosome. Sister chromatids separate and one from each pair moves poleward. Chromosomes have reached the poles; the nuclear membrane reforms around each group of chromosomes. The chromosomes begin to decondense and return to interphase. Mitotic spindle matures, taking on the spindle shape.
