SOCR 330 Lecture Notes - Galactose, Repressor, Galactoside
Document Summary
All cells contain entire genome but not all genes are expressed at all times. Other genes have more specialized functions and are expressed. Awarded nobel prize for medicine in 1965 for their work on the lac operon. Preferred sugar for atp production is glucose (monosaccharide) Slower to diffuse into cell: coli and lactose. To utilize lactose as energy source e. coli needs: Permease (makes cell wall more permeable to lactose) Galactoside transacetylase (prevents toxic buildup of lactose products in cell) Inefficient use of cell resources to express enzymes when not required. Up-regulate gene expression for the 3 enzymes needed. Glucose present repressor from i gene binds to operator and inhibits transcription. Glucose and lactose present lactose binds to repressor and releases it from operator. Lactose present but no glucose camp/cap complex binds to promoter, accelerates transcription. Since jacob and monod"s initial discovery additional research has shown.
