BIO 1140 Lecture Notes - Lecture 22: Tubulin, Nondisjunction, Cytokinesis
8 Oct 2016
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Internally: molecular switches (cyclins and cyclin dependant kinases cdk) Cdks need a cyclin to be active. These protein combinations control passage between each cell cycle stage. The levels of cdks (and cyclins) rise and fall during the cycle this controls each step. If expectations along cell cycle not met, cycle is interrupted. Each portion of the cell cycle requires a specific combination of cyclins and cdks. Mpf = maturation promoting factor = cyclin + cdk complex. At their peak when maximum combination with cdk so activity to move forward is maximum. Mpf maturation promoting factor, cdk and cyclin bound together. Cyclin concentration goes up and down (down when degraded) They are named according to the checkpoint they govern: G1/s cyclins (e): bind their cdk (2) near end of g1 and lead cell into dna replication: need everything required for dna replication, enough cell growth, enough nutrients, enough cell space.
