Biology 1201A Chapter Notes - Chapter 13: Lac Repressor, Operon, Lac Operon
Document Summary
Reviewing chapter 14, control of gene expression; especially the sections 14. 1a and. 14. 1b. identify the main features of bacterial operons. Operon: cluster of prokaryotic genes and the dna sequence involved in their regulation. Promoter where rna polymerase begin transcription another regulatory dna sequence in the operon is the operator: short segement that is a binding sequence for a regulatory protein. Some operons are controlled by a regulatory protein called the repressor, which when bound to dna, reduces the likelihood that genes will be transcribed. Other operons controlled by the activator (a regulatory protein) that when bound to. Dna, increases the likelihood that genes will be transcribed. Many operons are controlled by more than one regulatory mechanism, and a number of the repressors or activators control more than one operon. This provides regulation for transcription, allowing instantaneous changes to environemt. Bacteria are typically exposed to an ever-changing environment in which nutrient availability may increase or decrease radically.