Bio 201 1st Edition Lecture 25Outline of Last Lecture I. Non-Cyclic Electron TransportII. Cyclic Electron TransportA. The Calvin CycleOutline of Current LectureI. ProliferationII. The Cell CycleA. Interphase vs. MB. Frogs and The Cell CycleIII. Maturation Promoting FactorCurrent LectureI. Proliferation- The proliferation signal DNA replication cell midget-Bacteria have a single chromosome, and divide by fission:1. Replication of single, circular chromosome2. Segregation of chromosome and its copy3. Cytokinesis (segregation of daughter cells)-Eukaryotes divide by mitosis:1. Replication of centrosomes2. Replication of chromosomes, sister chromatids join at centromereThese 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.3. Nuclear envelope breakdown and beginning of chromosome alignment4. Alignment of chromosome at equator5. Segregation of sister chromatids6. Cytokinesis and reformation of nuclear envelopeII. The Cell Cycle- G1 S G2 M-Daughter cells must grow for the cycle to continue-G1= Gap 1= Growth-G0= Gap 0= Exiting Cell Cycle-S= Synthesis= DNA replication-G2= Gap 2= Cell stops, DNA checked for error-M= Mitosis= Chromosome condensation, cytokinesis (cell division)A. Interphase vs. M- G1, S, and G2 together are the same thing as interphase. All phases in which the DNA is invisible. If there is a stain in the nucleus, mitosis occurs. B. Frogs and The Cell Cycle- Frog oocytes (unfertilized eggs) will not progress through meiosis until they receive progesterone. Progesterone signals the oocytes to divide. Oocytes cells become “arrested” in G2. Experiment: 1. Treat oocyte 1 with P, 2. Extract cytoplasm from oocyte 1, 3. Injected cytoplasm extracted into untreated oocyte 2 M complete. Results in an untreated oocyte completing M and maturing into 2degree oocyte. Negative controls- Inject cytoplasm from cells in other stages of the cycle no effect.III. Maturation Promoting Factor (MPF)- The activity in the cytoplasm of progesterone-treated oocytes that stimulates completion of M phase. -MPF found in all cells at beginning of meiosis/mitosis-MPF activity from one cell triggers entry into meiosis into mitosis in any other cell arrested in G2-MPF activity begins to appear at the end of G2 and remains high until the end of mitosis-MPF activity is a complex of 2 proteins, Cyclin B and Cdk1. Cdk1- cyclin-dependent protein kinase (cdc 2). Cyclin B- allosteric activator of Cdk1, made by cells in response to progesterone, activates Cdk1 and after a fixed time Cyclin B degrades Cdk1 inactive. -Cdk1- phosphorylates proteins involved in mitosis. Targets; Histone protein chromosome condensation, Lamin A Nuclear envelope breakdown, Microtubule associated proteins Mitotic Spindle. -Diiferent cyclins activate Cdks progression through different phases of the
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