Chapter 28: Gene Regulation in E. coli

These flashcards cover key terms and concepts related to gene regulation in E. coli as discussed in Chapter 28 of the lecture notes.

lac repressor

A protein that inhibits the synthesis of proteins encoded by the lac operon by binding to the operator region.

cAMP

Cyclic adenosine monophosphate, a molecule that stimulates transcription of catabolite-repressed operons.

attenuation

A regulatory mechanism linking amino acid availability to operon expression, resulting in the premature termination of transcription.

riboswitch

A segment of RNA that changes conformation to regulate gene expression in response to small molecules.

operator

A region of the lac operon where the lac repressor binds to prevent transcription of mRNA.

E. coli

A type of bacteria that serves as a model organism in molecular biology and genetics.

β-galactosidase

An enzyme encoded by the lac operon that catalyzes the hydrolysis of lactose.

inducer

A molecule that triggers the synthesis of proteins in response to the presence of a substrate, such as lactose for the lac operon.

CAP (catabolite activator protein)

A protein that, in conjunction with cAMP, stimulates transcription of certain operons, including the lac operon.

catabolite repression

A phenomenon where the presence of glucose inhibits the expression of genes involved in the metabolism of other sugars.

IPTG (isopropylthiogalactoside)

A synthetic inducer that mimics allolactose but is not broken down by the enzyme β-galactosidase.

trp operon

A group of genes in E. coli that regulates the synthesis of tryptophan from chorismate.

corepressor

A substance that represses gene expression by binding to a repressor protein, such as tryptophan binding to the trp repressor.

attenuator

A sequence in the trp operon leader that regulates transcription termination based on tryptophan availability.

thi box

A conserved sequence in the untranslated regions of certain mRNAs that is involved in riboswitch activity.

ribozyme

A segment of RNA that can catalyze biochemical reactions, including the self-cleavage mechanism found in some riboswitches.

allosteric protein

A type of protein whose activity is regulated by the binding of an effector molecule at a site other than the active site.

Shine-Dalgarno sequence

A ribosomal binding site in bacterial mRNA that is essential for the initiation of translation.