GEN-3000 Chapter Notes - Chapter 15: Catabolite Repression, Cyclic Adenosine Monophosphate, Lac Operon
Document Summary
Chapter 15 control of gene expression: constitutive enzymes always produced, adaptive/facultative enzymes made when needed. Don"t waste energy if you don"t need it. *focus of this chapter: inducible production is (cid:862)on(cid:863) when an inducer is present. Off and we turn it on: repressible production is (cid:862)off(cid:863) when a product is present. Usually on and we want to turn off. In negative regulation we have a repressor on the operator. Inducer usually pulls repressor off to get transcription going. Prokaryotes have a neat way of organizing all of their genes. One single promoter, one single operator, so only have to get transcription going once. Operon- single transcriptional unit, contains series of genes, a promoter, and an operator transcriptional control - can be negative or positive. Promoter, operator and structural genes make up the operon. Regulatory gene makes the activator and the repressor. Inducible means transcription is usually off and we want to be able to turn it on.
