Regulation of Bacterial Gene Expression - The Operon

These flashcards cover the key concepts and vocabulary related to the regulation of bacterial gene expression, particularly focusing on operons.

Operon

A functioning unit of genomic material containing a cluster of genes under the control of a single regulatory signal or promoter.

Cis-acting sequences

DNA sequences that affect the activity of sequences on their own molecule of DNA, typically including promoters and terminators.

Trans-acting factors

Products of genes that can function on any copy of its target DNA, often proteins or RNA molecules.

Regulator gene

A gene that codes for a product that controls the expression of other genes, usually at the level of transcription.

Negative regulation

Control mechanism in which a repressor binds to an operator to prevent gene expression.

Positive regulation

Control mechanism where an activator binds to a promoter to enable transcription initiation.

Inducible regulation

Gene regulation based on the presence of a substrate (inducer) leading to the expression of a gene.

Repressible regulation

Gene regulation based on the presence of the product of its enzyme pathway (co-repressor) that suppresses gene expression.

Lac operon

An operon including genes that enable bacteria to metabolize lactose, regulated by the presence of lactose.

Attenuation

Regulation of bacterial operons by controlling termination of transcription at a site before the first structural gene.