Regulation of Gene Expression in Bacteria

These flashcards cover key vocabulary and concepts related to the regulation of gene expression in bacteria, focusing on operons, repressor proteins, and transcriptional control.

Negative control of transcription

Involves binding of a repressor protein to a regulatory DNA sequence, preventing transcription of a gene or gene cluster.

Positive control of transcription

Involves binding of an activator protein to a regulatory DNA sequence, assisting RNA polymerase in initiating gene transcription.

Repressor protein

A type of regulatory protein that exerts negative control of transcription by binding to sequences called operators.

Operator

The DNA sequence where repressor proteins bind to block transcription.

Allostery

The change in conformational shape of a protein caused by the binding of a molecule, affecting its function.

Inducible operon

An operon that is turned on only in the presence of an inducer molecule.

Operon

A cluster of genes that are regulated together, sharing a common regulatory region.

lac operon

An example of an inducible operon in E. coli responsible for the metabolism of lactose.

trp operon

A repressible operon involved in the biosynthesis of tryptophan.

Corepressor

A molecule that, when bound to a repressor, can activate the repressor and inhibit transcription.

Default state of gene expression

The state in which a gene is either turned off (repressed) or turned on (expressed) in the absence of regulatory signals.

Polycistronic mRNA

An mRNA molecule that contains multiple coding sequences corresponding to different proteins.

Operon structure

Contains a regulatory region (promoter and operator) and structural genes involved in a metabolic pathway.