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Unformatted text preview: 22:19 Cell division reproduction of cells Rudolf Virchow, 1855: Omnis cellula e cellula every cell from a cell Roles Reproduce (for prokaryotic cell/unicellular eukaryote) Develop from a single cell (multicellular eukaryotes) Renewal and repair Part of cell cycle Life of a cell from the time it is first formed from a dividing parent cell until its own division into two daughter cells Mostly results in genetically identical daughter cells Genome a cells endowment of DNA, its genetic information LOTS and LOTS of DNA in eukaryotic cells Packaged into chromosomes DNA + proteins = chromatin Human somatic cells contain 46 chromosomes, made up of 2 sets of 23, one set inherited from each parent Gametes have one set of 23 chromosomes (humans) Distribution of chromosomes during cell division After DNA replication, chromosomes condense Each duplicated chromosome has 2 sister chromatids (joined copies of the original chromosome) Initially attached along lengths by sister chromatid cohesions Have centromere (regions containing specific DNA sequences where the chromatid is attached most closely to its sister chromatid) Later, sister chromatids separate move into 2 nuclei (at opposite ends of the cells), now considered individual chromosomes Mitosis division of genetic material in nucleus Cytokinesis division of the cytoplasm Meiosis gametes are produced yields non-identical daughter cells that have only one set of chromosomes, occurs in the gonads (ovaries/testes) Mitotic phase and interphase in cell cycle Mitotic (M) phase: mitosis and cytokinesis cell division Interphase 90% of cell cycle, grows, copies its chromosomes G 1 phase (first gap) GROW! S phase (synthesis) copies chromosomes, GROW!...
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This note was uploaded on 03/14/2012 for the course BISC 220 taught by Professor Mcclure during the Spring '09 term at USC.
- Spring '09