The lac operon - The lac operon Lactose is a sugar found in...

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The lac operon Lactose is a sugar found in milk. If lactose is present, E. coli (the common intestinal bacterium) needs to produce the necessary enzymes to digest it. Three different enzymes are needed. 1.) Lac A 2.) Lac Y 3.) Lac Z In the diagrams below, genes A, B, and C represent the genes whose products are necessary to digest lactose. In the normal condition, the genes do not function because a repressor protein is active and bound to the DNA preventing transcription. When the repressor protein is bound to the DNA, RNA polymerase cannot bind to the DNA. The protein must be removed before the genes can be transcribed. Below: Lactose binds with the repressor protein inactivating it. The repressor protein is produced by a regulator gene . The region of DNA where the repressor protein binds is the operator site. The promoter site is a region of DNA where RNA polymerase can bind. The entire unit (promoter, operator, and genes) is an operon .
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This note was uploaded on 03/06/2011 for the course BIOL 100B taught by Professor Nargesshassanzadeh-kiabi during the Winter '08 term at California State University Los Angeles .

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The lac operon - The lac operon Lactose is a sugar found in...

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