Bio 101 Day 25

Bio 101 Day 25 - Control of the lac Operon -Repressor...

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Control of the lac Operon --Repressor Gene—constitutive structural gene that codes for a repressor protein --Promoter—site on DNA where RNA polymerase binds --Operator—site on DNA that is blocked by binding of the repressor protein --lac Z, lac Y, and lac A—structural genes that code for enzymes used in lactose metabolism Lactose Absent --Repressor Gene not part of the lac Operon --Repressor Gene is constitutive (always being transcribed) Repressor Gene Transcription mRNA Ribosome Translation Repressor Protein --Repressor Protein attaches to the lac Operon --No transcription occurs of genes along lac Operon What happens if lactose is present? --Some lactose eneters the cell and is converted to allolactose --Allolactose binds to the repressor and inactivates it --Allolactose is the inducer for the lac Operon Lactose Present --Repressor Gene is constitutive (not being affected by whether lactose is present or not --Make repressor --Repressor binds to incuder (allolactose) --Repressor Protein becomes inactivated can’t bind to the operator --RNA polymerase can bind to promoter and there is nothing in its way
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This note was uploaded on 04/06/2010 for the course BIO 01-119-10 taught by Professor D'arville during the Fall '09 term at Rutgers.

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Bio 101 Day 25 - Control of the lac Operon -Repressor...

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