BIOCH330 Lecture Notes - Lecture 10: Lac Operon, Lac Repressor, Operon

• School: University of Alberta
• Department: Biochemistry
• Course: BIOCH330
• Professor: Andrew Macmillan

Document Summary

A set of genes related to a speci c pathway that require multiple steps. Those genes are transcribed as a unit. There can be operator sites - sequence that is bound speci cally by a repressor protein. There an be activator binding sites that activate transcription typically by stabilizing the polymerase at the promoter. Series of genes involved in the metabolism of lactose. Lactose is a source of energy for the cell. The enzyme b-galactosidase cleaves lactose to give galactose and glucose. 3 genes, 2 operons, promoter(for lac operon) and then a laci upstream of that. Lac i codes for the lac repressor. Lac repressor binds to the operator sites. Theres also positive regulation of lac operon by cyclic amp that binds to a receptor protein. In the absence of lactose there is no need to produce these proteins involved in lactose metabolism. ^ will be a waste in energy.