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Unformatted text preview: b. Repress (inhibit) enzyme production in the absence of the substrate 3. Operon consists of: a. Regulator gene – codes for repressor protein b. Operator gene – binding site for repressor protein c. Promoter gene – binding site for RNA polymerase 4. Lac operon a. In absence of lactose: 1). Repressor protein binds to operator gene 2). RNA polymerase cannot bind to promoter gene 3). Production (transcription) of enzymes required for lactose metabolism prevented b. In presence of lactose: 1). Lactose molecules bind to repressor protein → inactivated 2). Inactive repressor protein cannot bind to operator gene 3). RNA polymerase binds to promoter gene → transcription 4). Production enzymes required for lactose metabolism 4. See operation of Lac operon in figure in text...
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.
- Fall '09