BIOS 10161 Lecture Notes - Lecture 13: Lac Operon, Catabolite Repression, Galactoside
21 Sep 2016
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Document Summary
Prokaryotes can make some proteins only when they are needed, so they can shut off a protein supply. They do this by: down regulation of mrna transcription, hydrolyze mrna prevents translation, prevent mrna translation at the ribosome, hydrolyze the protein after its made, inhibit protein function. Earlier protein synthesis is stopped less wasted energy: blocking transcription is more efficient than degrading the protein post transcription and translation. Two ways in which metabolic pathways are regulated: allosteric regulation of enzyme catalyzed rxns allows rapid fine tuning, regulation of protein synthesis is slower but conserves energy and resources (because protein synthesis requires hella energy) Gene expression regulation begins at the promoter: two types of regulatory proteins that bind to the promoters: Positive regulation activator protein stimulates transcription. E coli in the human intestine must adjust quickly to changes in food supply: glucose easiest sugar to metabolize, lactose - galactoside (galactose + glucose)
