国外大学细胞生物学课件 英文课件21.ppt

Page 1 D103 - Cell Biology - lecture 20 ? 2011 Grant MacGregor & Christine S ü tterlin - all rights reserved Lecture 20 – Cell Cycle I Overview and Key Principles of the Eukaryotic Cell Cycle mended Reading: MBOC 5e, pages 1053 - 1070, 1100 - 1110 Page 2 D103 - Cell Biology - lecture 20 ? 2011 Grant MacGregor & Christine S ü tterlin - all rights reserved Functions for cell division ? Provide a source of cells to develop a body (. development ). ? Provide a supply of cells to maintain a body (. adaptation / homeostasis ). Essential goals required to undergo cell division ? Increasecell size (except early embryogenesis). ? Make an accurate copy of the genome . ? Segregate the duplicated genome to each of the daughter cells .? anelles to each of the daughter cells . What if the cell gets it wrong ? ? Insufficient division = growth retardation, degeneration. ? Excessive division = birth defects, cancer. ? Incorrect segregation of chromosomes = similar effects. Cell Division - what are the goals, what happens if things go wrong ? Page 3 D103 - Cell Biology - lecture 20 ? 2011 Grant MacGregor & Christine S ü tterlin - all rights reserved The eukaryotic cell cycle posed of interphase , mitosis &cytokinesis Interphase : Cells grow and replicate DNA. Consists of three stages - ?G 1 phase - first ‘ gap ’ phase. ? S phase - DNA synthesis. ?G 2 phase - second ‘ gap ’ phase. “ Gap ” phases - named because nothing appeared to be happening during these periods. Advent of molecular biology revealed significant cellular activity during these stages. Mitosis : ( mito : Greek thread ) portion of cell cycle when a fully grown cell segregates the duplicated chromosomes to opposite ends of a microtubule scaffold (spindle) . Cytokinesis : Cleavage of cell to produce two daughter cells. Page 4 D103 - Cell Biology - lecture 20 ? 2011 Grant MacGregor & Christine S ü tterlin - all rights reserved The rate of cell divisio