Week 3 S - Gene Regulation in Prokaryotes

Flashcards covering key vocabulary and concepts related to gene regulation in prokaryotes, focusing on the lac operon.

Repressor Protein

A regulatory protein that prevents gene transcription.

Allolactose

An isomer of lactose that acts as an inducer of the lac operon.

Catabolite repression

The repression of genes usually involved in catabolism of other sugars when glucose is present.

Diauxic growth

Growth in two phases, often seen when bacteria utilize glucose first, then switch to lactose.

Gene regulation

Allows rapid responses to environmental changes, enabling bacteria to adapt their physiology.

Control points in gene expression

Transcription, transcript processing, and translation.

Transcription

The main control point in bacterial gene expression.

Operon

A unit of genetic material consisting of a promoter, an operator, and structural genes that are transcribed together

Operator

A cis-acting element where regulatory proteins bind.

Polycistronic transcript

Multiple genes transcribed from one promoter into a single transcript.

lacI

A gene encoding the lac repressor protein.

lacZ

The structural gene that codes for β-galactosidase.

lacY

The structural gene that codes for permease.

lacA

The structural gene that codes for transacetylase.

Promoter

The region where RNA polymerase binds to initiate transcription.

Inducer

A molecule that induces gene expression by binding to a repressor protein.

IPTG (Isopropylthiogalactoside)

A gratuitous inducer of the lac operon that is not degraded by β-galactosidase.

DNA-binding domain

A protein domain that binds to DNA.

Palindrome

A DNA sequence with an inverted repeat.

cAMP (Cyclic AMP)

A signal molecule involved in catabolite repression.

CRP (cAMP Receptor Protein)

A positive regulatory protein that binds cAMP.

Co-effectors

Small molecules/chemicals that cause expression or repression of specific genes.

Cis-acting mutations

Mutations that affect the entire operon but cannot be complemented.

Trans-acting mutations

Mutations that affect the entire operon and can be complemented.