unit 4 operons

Operon

a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway

Genes of an Operon

arranged sequentially after the promoter

Promoter

a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place

Regulatory Gene

codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes

Operator

regulatory proteins bind to this to control expression of the operon

Repressor

a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter

Inducer

a specific small molecule that binds to a bacterial regulatory protein and changes its shape so that it cannot bind to an operator, thus switching an operon on