Metabolic Regulation Flashcards
Where does metabolic regulation take place?
At the genetic and cellular level
In what types of cells does transcriptional control take place?
Bacterial cells.
What is transcriptional control in bacteria?
The cell senses that it has too little or too much of a particular protein and it responds by increasing or decreasing the rate of transcription of that gene.
Two forms of regulation
- Feedback repression
2. Induction
What is feedback repression?
The end product of enzymatic activity accumulates and blocks transcription
What is induction?
A metabolite (often a substrate for a pathway) accumulates and acts as an inducer of transcription.
In repression of transcription where does the repressor and co-repressor bind?
The end product of enzymatic activity or the product of a metabolic pathway (metabolite/ co-repressor) will block m-RNA synthesis by binding to the operator. The repressor can only block transcription when a co-repressor is present.
In induction of transcription where does the substrate from the metabolic pathway bind?
A substrate from the metabolic pathway accumulates, induces m-RNA synthesis by binding to the repressor that was on the operator.
What is an operon?
It is a set of contiguous genes (encoding proteins with related functions) under the control of a single promoter region.
Give an example of an operon
Lac operon. Controls the synthesis of the three proteins involved in lactose utilisation as a carbon energy source in E. coli. E-coli will not use lactose as an energy source unless the preferred substrate (glucose) is fully consumed.
