Transcript cell cycle
Cell Division • Prokaryotic binary fission sporulation • Eukaryotic mitosis meiosis Prokaryotic Cell Division - Binary Fission Eukaryotic DNA is Packaged into Chromosomes Chromosomes, Chromatids, and Chromatin spectral karyotype Karyotypes Numbers of Chromosomes in Some Plant and Animal Species Yeast Saccharomyces cerevisiae 16 Mitosis The Mitotic Spindle Consists of Microtubules Mitosis Mitosis Cytokinesis Differs in Animal and Plant Cells The Eukaryotic Cell Cycle Checkpoints in Cell Cycle Progression • G1 to S and G2 to M transitions are regulated by proteins called cyclindependent kinases (Cdks) and cyclins Cyclin proteins and Cdk activity • Cyclin proteins are made and destroyed in a cyclic pattern during the cell cycle • Cdks are activated by binding to one of several different cyclin proteins Cyclins and activation of Cdks Cyclin-Dependent Kinases and Cyclins Regulate Transitions in the Cell Cycle MPF • Cdk-cyclin complexes each phosphorylate different target proteins to regulate progression of the cell cycle p53 Disruption of Cell Cycle Control • Cyclin-Cdk complexes act as checkpoints. • When functioning properly, they allow or prevent passage to the next stage of the cell cycle • In cancer cells, these checkpoints are often disrupted Rb/p105 (retinoblastoma) Loss of Rb permits unregulated cell division p53 Loss of p53 prevents synthesis of p21 which allows production of cyclin D Asexual Reproduction Meiosis and Alternation of Generations in Sexual Reproduction Meiosis I Crossing Over Forms Genetically Diverse Chromosomes Meiotic Recombination Chiasmata: Evidence of Exchange between Chromatids Meiosis I Meiosis I Meiosis II Meiosis II Meiosis II Mitosis and Meiosis: A Comparison Mitosis and Meiosis: A Comparison Nondisjunction Leads to Aneuploidy Apoptosis: Programmed Cell Death Two Different Ways for Cells to Die