Mitosis and Meiosis
When going over the cell cycle, mitosis and meiosis are two major components. Mitosis is the division of the cell’s nucleus, and is followed by cytokinesis. Cytokinesis is the division of cytoplasm. Mitosis is only one phase that a cell goes through in the cell cycle. Also the mitotic phase is one of the shortest phases. Mitosis can be broken down into five different stages; prophase, prometaphase, metaphase, anaphase, and telophase. In prophase the nucleoli starts to disappear, and the mitotic spindle begins to form. Also the duplicated chromosomes are identical sister chromatids that are connected at the centromeres. Prometaphase is where the nuclear envelope fragments. The chromosomes become more condensed, and some of the microtubules attach to the kinetochores. In metaphase is the longest stage that occurs in mitosis. The centrosomes are at opposite poles of the cell now. Also the chromosomes convene on a metaphase plate between the two poles. Anaphase is the shortest phase, where the two chromatids part. Now the two separate chromosomes move to opposite ends of the cell. By the end of anaphase the two ends of the cell have complete and equivalent set of chromosomes. Telophase is where the nuclei form in the cell, and nucleoli reappear. The chromosomes are less condense in this phase, and the cycle of mitosis is now complete followed by cytokinesis.
Meiosis is cell division that reduces the number of sets of chromosomes from two to one in the gametes. It counterbalances the doubling that occurs at fertilization. This single replication is followed by two consecutive cell divisions, meiosis I and meiosis II. There are the same four stages in each parts of meiosis. In meiosis I the prophase I the chromosomes begin to condense, and align gene by gene. Synapses ends midway through prophase, and chromosomes in each pair move apart. In metaphase I pairs of homologous chromosomes now arrange on the metaphase plate. Anaphase I the breakdown...
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