1、Cell proliferation and its regulationSignificance:1. For the growth and development of a multicellular organism, and for the generation of offspring; 2. Produce new organisms in unicellular species;3. Renew the aging, apoptotic cells, and damaged tissue;So, cell proliferation is one of the most impo
2、rtant characters for lifeChapter 11If damaged seriously by UV, mouse will die within several days.1. The cell cycleA. Overview of the cell cycleThe most basic function of the cell cycle is to duplicate accurately the vast amount of DNA in the chromosomes and then segregate the copies precisely into
3、two genetically identical daughter cells.vCell cycle phases:Interphase: G1-S-G2M phase: Mitosis, Cytokinesisv Different cell cycle lengthSome eukaryotic cell cycle timesThe greatest variation occurs in the duration of G1The shortest eukaryotic division cycles of all are the early embryonic cell cycl
4、es, no G1 and G2v Biochemical events of cell cycleG1 phase: Synthesize proteins (RNA) for the DNA replication. Uncondense chromatin.S phase: Synthesis of DNA and HistonesG2 phase: Synthesis of a few proteins (RNA)M phase: Mitosis and meiosis and cytokinesisTwo daughter cellsChromosome condense Mitot
5、ic spindle Contractile ringv Three categories of cells in vivo(1)Cycling cells(2) Dividing continuouslyStem cells(2) G0 cellsDo not divide normally, but divide when given an appropriate stimulus: liver cells, lymphocytes(3) Terminally Differentiated cellsHighly specialized, have lost the ability to divide until they die: muscle cells, red blood cells, nerve cells Embryo cellsCycling cellsG0 cellsTerminal cells
