BIO 1140 Lecture Notes - Lecture 15: Lac Repressor, Repressor, Allolactose
8 Oct 2016
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Document Summary
Regulation is achieved through operons; genetic switches that control transcription (on/off) Dna to mrna mrna into protein (translation) Prokaryotes gene expression controlled via operons. Operons area that allows on/off switches. Operator adds additional on/off switch, where the repressor binds, when bind prevents polymerase from reading dna sequence. When is repressor available lactose available, prevents repressor from binding to. The product of the transcription of an operon is one _____________. Set of related mrnas that code for functionally related proteins. Translation ribosome reads entire coding region of mrna, turns it into proteins. Why lactose repressor in absence of lactose no lactose to breakdown, no need to spend energy transcribing/translation enzymes to break down lactose. Repressor binds to operator, stops polymerase (can"t move forward), transcription is blocked in absence of lactose. Not 100% efficient because still needs a bit of the enzymes available; not covalent bond, still can fall off the operator, polymerase can then keep going.
