Unformatted text preview: the controller molecule binds to the repressor. When that happens, the repressor, with its controller attached, actively blocks transcription. Inducible Operon Repressible Operon We will look at two prokaryotic operons: the lactose operon, an inducible operon and the tryptophan operon, a repressible operon. The Lactose Operon – An Inducible Operon To get an idea of how genes get regulated, we will look at the Lactose operon, described by Jacob and Monod in E. coli . The lactose operon contains the three genes that code for the enzymes that degrade lactose. In the absence of lactose, the controller substance, the repressor inhibits transcription by blocking RNA polymerase from attaching to the promoter....
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- Spring '10
- DNA, repressible operon, lactose operon