BIO206H5 Lecture Notes - Lecture 18: Catabolite Activator Protein, Lac Operon, Operon
Document Summary
Positive regulation: not all promoters are equally efficient, some forms of transcription regulation act to improve the efficiency of the promoter by improving the binding of the rna polymerase. e. g. lactose operon: both negatively and positively regulated. Some promoters are more efficient at initiating transcription than other promoters are; thus some genes are weakly expressed and some are strongly expressed; improve the binding of the rna pol to the promoter. General term for cellular enzyme-catalyzed reactions in which complex molecules are degraded to simpler compounds with the release of energy. Intermediates in the biochemical pathways are called catabolites. Glucose builds up in the cell as a result of the catabolism of lactose. Glucose increase inhibits the b-galactosidase synthesis (represses expression of this gene) Positive regulation in the lac operon: cap binding site: dna sequence upstream of the promoter, regulator protein: catabolite activator protein (cap, cap regulated by camp: only cap + camp can bind to dna.
