BIOLOGY 1A03 Study Guide - Midterm Guide: Adenylyl Cyclase, Disaccharide, Escherichia Coli

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

Document Summary

When e. coli cells in environment that contains glucose and disaccharide lactose, bacteria will metabolize all glucose before switching to lactose as a fuel source; quickly upregulate (increase) expression of genes that produce lactose- metabolizing enzymes. Metabolic shift in nutrient source utilization, tightly regulated process in bacteria. Control of enzyme production regulated at transcriptional level. Transcription of many genes in e. coli genome turned-on for change in nutrient source. Enable metabolic shift by detecting environmental cues that facilitate transition from glucose to lactose metabolism, include changes in glucose levels and the presence of lactose. As e. coli cells transition from glucose to lactose metabolism, there is increase in detectable beta-galactosidase and lactose permease proteins. Not detectable when e. coli cells utilizing glucose as primary nutrient source, but are soon expressed as they are required for transport and metabolism of lactose. Not expressed until glucose fully depleted from growth medium.