Regulation by repressio1

Regulation by repressio1 - Regulation by repression...

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Regulation by repression, induction and attenuation The lac Z gene encodes ß-galactosidase , which catalyzes hydrolysis of lactose into glucose and galactose · The lac Y gene encodes lactose permease , which is involved in transport of lactose into the cell · The lac A gene encodes transacetylase, which is of uncertain significance in lactose metabolism · These three proteins are all translated from a single mRNA molecule = As with all transcribed DNA units, the lac operon includes a promoter that is recognized by RNA polymerase = Between the lac promoter and the structural genes is the lac operator , a regulatory site - The lac repressor , which is involved in regulation of the lac operon, is transcribed from a separate gene, the lac I gene; this gene has its own promoter - In the absence of lactose, transcription of the lac operon genes is prevented from occurring at significant levels
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