BIOL 1107 1nd Edition Lecture 10 Outline of Last Lecture I Reduction Oxidation Reactions a NAD and NADH b Electronegativity II Cellular Respiration a Glycolysis Phosphorylation b Pyruvate c Citric Acid Cycle d Electron Transport Chemiosmosis Outline of Current Lecture I Interphase a G1 Phase b S Phase c G2 Phase II Mitosis a Prophase b Prometaphase c Metaphase d Anaphase e Telaphase III Cytokinesis IV Mitosis vs Meiosis V Meiosis VI Meiosis Current Lecture I Interphase Chromosome replication occurs only during interphase Cells in the central nervous system spinal column do not divide so if they die that s it Blood cells also don t divide because they have no nucleus In interphase cells are not resting they are just not going through mitosis Also most chromatin is relaxed or uncondensed a G1 Phase parent cell 4 un replicated chromosomes protein complexes that wrap around DNA to form chromosomes must be available otherwise it goes to G0 These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute b S Phase parent cell DNA synthesis DNA replication itself if errors occur cells correct them but if they do not get corrected the cell does not go to G 2 c G2 Phase parent cell check phase to make sure cells are correct cancer forms because something went wrong is S phase and were not noticed corrected and they go on to be divided and form cancerous cells cells get by G2 because the cells inhibit check points ignoring G2 II Mitosis daughter cells During mitosis the two sister chromatids separate to form independent chromosomes and one copy of each chromosome goes to each of the two daughter cells As a result each daughter cell receives a copy of the genetic information that is contained in each chromosome division of nucleus a Prophase Chromosomes condense and spindle apparatus forms b Prometaphase Nuclear envelope breaks down c Metaphase Chromosomes complete migration to middle of cell d Anaphase Chromatids separate and are pulled to different sides of the cell e Telaphase Nuclear envelope re forms III Cytokinesis The cell itself divides into two cells IV Mitosis vs Meiosis Only those who carry out sexual reproduction goes through meiosis Involves a maternal side and a paternal side in meiosis homologous chromosomes are half maternal and half paternal In meiosis chromosomes have different length having a different number of genes V Meiosis Similar to mitosis however homologous pairs cross over and exchange information as well as line up differently the sister chromatids line up side by side as opposed to end to end Homologous chromosomes cross over even exchange so genetic information transfers and copies causing variation which happens in prophase of meiosis Don t want crossing over to occur in mitosis because you want the same cells replaces without variation VI Meiosis Sister Chromatids separate they line up end by end crossing over cannot happen in meiosis because only prophase can digest the binding protein that holds the sister chromatids together
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