BIOL 2020 Study Guide - Final Guide: Lac Repressor, Beta-Galactosidase, Lac Operon
Document Summary
Potent chemotherapeutic agents, antibiotic inhibitor of bacterial rna synthesis effective for treating uberculosis. Requirements for rna polymerase (3: template, dna template, coding-sense. Describe elongation, transcription bubble. (+), template-antisense (-: activated precursors, ribonucleoside triphosphates (atp, gtp etc, divalent metal ion (cofactor) mg 2+ or. Elongation similar to 3"-oh group at the terminus of growing chain attacks inner most phosphoryl group of incoming ribonucleoside triphosphate. Driven forward by hydrolysis of pyrophosphate (doesn"t require a primer) 5 subunits, holoenzyme (alpha2beta2sigma) sigma finds transcription site, initiation of synthesis then dissociates. Rna without this is called the core enzyme. Promoters (dna sequences) direct rna polymerase to proper site, dna sequence are present on teh 5" upstream side (10 site/pribnow box) and (35 sequence) nucleotide # from start site. Promoters, weak prmoters also tend to have multiple substitutions at these site. Decreases affinity of rna polymerase by a factor of 10^4, allows dna to slide along it, core enzyme binds tightly to dna, also enables.