LIFESCI 3 Study Guide - Final Guide: Inverted Repeat, Lactose Permease, Lac Operon
Document Summary
Different cells express different genes at different times on different levels. Even though prokaryotes only have one cell, different genes are still expressed at different times on different levels bc it depends on the contents of growth medium. Gene expression is regulated at different steps. Especially at initiation bc it doesn"t want to waste energy if the gene isn"t needed, it doesn"t want to start initiation. Benefit to regulating at later steps: fast response time just in case there is something toxic that enters & you need that protein to fight it. This is transcription dna, rna polymerase, etc. Promoter strength = promoter that is efficient at recruiting machinery & initiating transcription event. Regulatory proteins = change gene expression levels to respond to different requirements for gene. Binding site is adjacent to promoter so it helps bring rna polymerase to bind. Bind to site that overlaps promoter called operator sequence. Blocks rna polymerase from binding altogether (specific to prokaryotes)
