BIOLOGY 1A03 Lecture Notes - Lecture 3: Permease, Operon, Repressor

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

E. coli cells in an environment with glucose and lactose will metabolize all the glucose before switching to lactose through a highly regulated process. Metabolic shift in nutrient source is tightly regulated such that they are able to quickly upregulate the expression of genes that produce lactose- metabolizing enzymes. Control of enzyme production is regulated at the transcriptional level. Transcription of gene sin the e. coli genome are turned-on to accommodate for this change in nutrient source. Two important cues detected by e. coli, changes in the glucose levels and presence of lactose. Concomitant increase in the amount of detectable beta-galactosidase and lactose permease proteins. Proteins not detectable when e. coli cells are utilizing glucose, but are soon expressed as they are required for the transport and metabolism of lactose. Proteins produced in response to environmental cues, and allows for the effective digestion of lactose.