Final Exam: Operon and Gene Regulation Flashcards
Define operon
A unit of bacterial gene expression and regulation including structural genes and regulatory elements
Define Structural gene
A gene that codes for any RNA or protein product other than a regulator
Define regulator gene
A gene that codes for a product that controls the expression of other genes
Define Cis-acting
A site on its own molecule
A site that affects the activity only of sequences on its own molecule of DNA.
Define trans-acting
Diffusible product that can function on any cis-acting site
A product that can function on any copy of its target DNA
Define negative control
A mechanism of gene regulation in which a regulator is required to turn the gene off
Define positive control
A system in which a gene is not expressed unless some action turns it on
Define inducer
A small molecule that triggers gene transcription by binding to a regulator protein
Define corepressor
A small molecule that triggers repression of transcription by binding to a regulator protein
Define permease
Transports lactose into the cell
Define the components of the lac repressor
lacI = repressor
lacZ = beta galactosidase
lacY = permease
Define allosteric control
Regulation of a protein by binding of a molecule at one site that changes activity of the protein at another site
Define Catabolite repression
The ability of glucose to prevent the expression of a number of genes. Positive control system in bacteria.
Define CRP
Catabolite repressor protein: a positive regulator protein activated by cAMP. It is needed for RNA polymerase to initiate transcription of many operons of ecoli.
-cAMP binds to CRP and converts it to a form that binds the promoter. This assists the RNA polymerase in initiating transcription
