BIOL207 Chapter Notes - Chapter 6: Lac Operon, Adenylyl Cyclase, Post-Translational Modification

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL207
• Professor: John Locke

Document Summary

The lac operon: a model prokaryote gene: jacob & manod, studied mechanisms of transcriptional regulation on e. coli, operon. When lac is high, lactose binds to laci preventing the repressor from binding to o and allowing transcription by rna polymerase. Atp: best expression of lac operon in e. coli, presence of lactose and absence of glucose. The use of mutants to study the lac operon. Single mutants of the lac operon: mutations can occur in lacz, lacy, laca genes, result in altered protein sequences and non functional products. Non regulatory mutations because they are in protein coding sequence: constitutive mutatnts, always on and unregulated by inducers, result in lac operon being expressed/transcribed whether or not lactose is present. E. coli strain with i+z-y+a+/f i-z+y-a+ will not produce lacz, lacy and laca products. The lac i gene has two independent functional domains which allows it to mutate independently and give two different types of mutant repressor proteins.