BIOL 1510 Lecture Notes - Lecture 8: Lac Operon, Galactoside, Permease
Document Summary
Set 8 process of converting information that is archived in dna into molecules that actually do things in the cell. Jacob and monod - discovered gene in bacteria that is only expressed in presence of lactose, three genes controlled by same promoter. Where rna polymerase attaches, 1 promoter for several genes ~ sigma positions rna polymerase over promoter. Operator sequence section of dna where repressor protein binds. Lactose binds to repressor protein and releases due to change in shape of protein, transcription can now occur. Repressor protein that does not work so transcription occurs constitutively. Large presence of lactose so binds to repressor protein and it releases, allowing lac operon to be expressed. If there is more glucose then lactose, repressor protein will not release and the lac operon will not be expressed. Negative control regulatory protein binds to dna blocking transcription. Postive control regulatory protein binds to dna enabling transcription.