Mitosis and Meiosis 92907

Mitosis and Meiosis - 1 to S(INSIDE THE CELL However major point One more substance is necessary to complete the transition Retinoblastoma protein

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Mitosis and Meiosis 1. Cell cycle for most cells has two phases: Division and Interphase Interphase has three sub-phases: G 1 ---S---G 2 Division: Mitosis or Meiosis and Cytokinesis Purpose of G 1 prepare for S (may at some point go to G 0 ) Therefore, G 1 can be thought of as a transition phase Problem: How are decisions made? Must activate proteins called Cyclin-dependent Kinases or Cdk’s Cdk’s catalyze the phosphorylation of specific (target) proteins. How is Cdk activated? Another protein binds to it, Cyclin forming what is termed a Cyclin-Cdk complex that then acts as a protein kinase and triggers the transition from G
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Unformatted text preview: 1 to S. (INSIDE THE CELL****) However, major point!!!!!!!!!!!!!!!! One more substance is necessary to complete the transition!!!!!!!!!!!!!!!! Retinoblastoma protein, otherwise known as (RB). RB is an inhibitor that then must be inhibited!!!!!! Yes Cdk’s phosphorylate RB which then becomes inactive and only then can G 1 move to S Why so significant? Well, over stimulation (production of Cdk) leads to more inhibition of RB which then can lead to an over production of new cells....
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This note was uploaded on 05/27/2008 for the course BIOLOGY 107 taught by Professor Dr.abbott during the Fall '08 term at UConn.

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