BIOL 2153 : Final Exam
Document Summary
Chapter 16: geneticists have learned that highly efficient mechanisms have evolved to turn transcription of specific genes on and off depending on the cell"s metabolic need for the gene"s products, regulation, 1. Inducible enzymes: produce certain enzymes only when specific chemical substrates are present, substrate serves as inducer, ex. Transcriptional: binding of rna polymerase to promoter, key step/ most common, shift from transcriptional initiation to elongation, release of the mrna at termination, 2. Post-transcriptional impact different phases of pathways: mrna stability, efficiency of ribosomes recognizing translational signals, polypeptide stability. Classic model for gene regulation: e. coli need sugar as a source of carbon and energy, clicker, which carbon source does e. coli prefer, glucose. Lactose has to be broken down into glucose first: made up of galactose and glucose, adding lactose leads to a 1000-fold increase in protein synthesis, thus, inducible, and lactose serves as the inducer.
