Biology 1201A Lecture Notes - Lecture 14: Lac Repressor, Allolactose, Repressor
Document Summary
Lac operon: lactose absent: rna polymerase cannot bind & cannot transcribe operon, allows for basal level of transcription, low levels of product of 3 genes produced. Promoter region: cap-site: when cap protein is bound to cap site - > makes polymerase favourable to transcribe genes. When activated by camp- inversely related to glucose levels- low glucose levels. 2 repressor: negative cap site: positive: if lactose is present, deactivate repressor. Trp operon: way biosynthetic pathways operate, promotor, operator, number of different genes involved inc. repressor genes, ex. repressor binding to operator, activator: turns on, tryptophan: acts w/ inactive repressor - > active repressor. Prokaryotic gene regulation: need to have different ways to control gene expression, eukaryotic: regulation is at level of transcription primarily- waste energy to transcribe something you don"t need b/c it will be translated as well. Eukaryotic gene regulation: different levels of protein production, based on structure of mrna, how modified after produced-i. e. spliced, times available for transcription.