BIOLOGY 172 Lecture Notes - Lecture 28: Nuclear Membrane, Cytokinesis, Cyclin A
Document Summary
Cell cycle: cell growth and division are tightly controlled, most cells in multicellular organisms do not divide, frequency of cell division varies, i. e. ) frog embryos divide every 30 minutes, human liver cells take up to 1 year. Complexity: developmental stage (cell type, stage, nutritional status, metabolic status (limited by resources, wound response, dna damage (as long as you have repair mechanisms, it won"t lead to mutations, pathogenesis, senescence (more and more cells exit cell cycle) Each of the two dna strands is replicated in chromosomes. In interphase, the dna is very mixed up and there is a clear nuclear envelope. In mitosis, the nuclear envelop breaks down and there are visible chromosomes, the spindle apparatus moves to the opposite poles of the cell and pulls chromosomes to opposite sides of cell. In cytokinesis the cytoplasm divides, forming two cells: animals: cytoskeletal ring squeezes, plants: build new cell wall and membrane between cells.
