BIOLOGY 1A03 Lecture Notes - Lecture 15: Lactose Permease, Beta-Galactosidase, Tetrameric Protein

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

Document Summary

Theme 3, module 2: prokaryotic transcriptional regulation; dr. kaijura; 4 october 2014; lecture and module notes. Enzyme production (to metabolize glucose/lactose) is done at the transcriptional level. E. coli cell use nutrients available in the environment detect environmental cues to transition from glucose to and the bacteria cells lactose. Environmental cues: changes in the glucose levels, presence of lactose. = beta-galactosidase and lactose permease proteins: proteins transport and metabolize lactose, proteins only expressed once glucose is fully depleted. Lactase permease: protein in cell membrane; transport of lactose into the bacterial cell. Beta-galactosidase: protein cytoplasmically situated; cleaves the lactose into glucose and galactose into operons (vs. eukaryotes with each gene = own promoter and enhancers) = prokaryotes have ability to control the transcription of the whole gene cluster. Advantage to prokaryotic genome: groups of genes with similar functions cluster together. Operon controls on-off switch coordination: consists: promoter, operator and gene.