ANPS 019 Lecture Notes - Lecture 5: Prophase, Sister Chromatids, Autophagy
14 Sep 2018
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Document Summary
Synthesis of proteins and rna for maintenance activities. Synthesis of proteins needed for s phase. Length of g1 stage is variable between cells (hours, days, weeks, etc) Replication of dna: each of 46 chromosomes is duplicated to form a sister chromatid. Chromatin condenses into chromosomes, each with 2 sister chromatids joined at region called centromere. Centrioles move to opposite poles of cell. Chromatids align at the center of mitotic spindle. Nuclear membranes reform around the two areas of chromatids to form new nuclei. Cytokinesis a cytoplasmic event overlapping the end of mitosis. Actin network pulls membrane into cleavage furrow. Furrow grows across to separate cytoplasm into new cells. Two key classes of genes produce proteins that regulate the cell cycle. Proto oncogenes : genes whose normal protein products stimulate the cell cycle. Oncogenes : mutated versions of these genes lead to deregulated cell cycle and abnormal growth (cancers) Tumor suppressor genes : genes whose normal protein products repress cell division.
