BIOL239 Lecture Notes - Lecture 9: Lac Repressor, Lac Operon, Permease

• School: University of Waterloo
• Department: Biology
• Course: BIOL239
• Professor: Laura Lemieux

Document Summary

Regulated at all levels: transcription, rna processing, rna stability, translation, post-translation, and protein function. Promoter region has to sequence regions that are critical for transcription: tata box (-10 region, 10 bp upstream from +1 of transcription region, ttg box (-35 region, 35 bp upstream from +1 of transcription region) 10 and -35 units provide a binding site for the sigma factor that escorts rna polymerase in. The presence of lactose induces expression of the genes required for lactose utilization in the cell. Addition of lactose to growth medium induces a 1000x increase in production of; permease and beta-galactosidase. Permease transports lactose into the cell (opens the plasma membrane) Beta-galactosidase changes bonds within lactose to form allolactose , then it breaks those bonds to release 2 molecules; glucose and galactose (glucose extraction for energy). Lack of lactose being brought into the cell halts production of permease and beta-galactosidase. 3 genes involved with the production regulation of lactose-utilization factors.