Biology 1002B Chapter Notes - Chapter 14: Cyclic Adenosine Monophosphate, Galactose, Allolactose
Document Summary
14. 1 regulation of gene expression in prokaryotic cells. 14. 1a the operon is a unit of transcription. On/off control for genes is at the level of transcription. Proposed by francois jacob and jacques monod in 1961. Operon cluster of prokaryotic genes and dna sequences involved in their regulation. Operator short binding sequence for a regulatory protein. Repressor protein that controls regulatory protein: reduces transcribing likelihood. Activator protein that controls some operons and: increases transcribing likelihood. Complex network of controls providing regulation of transcription and instantaneous responses to environmental changes. Transcription unit cluster of genes transcribed into mrna molecule. 14. 1b the lac operon for lactose metabolism is transcribed when an inducer. Involves 3 genes lacz, lacy, and lacz: in z-y-a order on the chromosome. Operator is between the promoter and lacz gene: controlled by the lac repressor, lac repressor is coded for on the laci gene close by to the lac operon.