Lactose Operon and Gene Regulation in Bacteria

Constitutive genes

Genes expressed constantly, regardless of conditions.

Inducible genes

Genes expressed only when their products are needed.

Beta galactosidase

Enzyme that breaks down lactose into glucose and galactose.

Lactose operon

Operon unique to bacteria, regulates lactose metabolism.

Gene expression

Process of making proteins coded by genes.

Operon

Group of genes controlled by a single promoter.

Promoter

Site where RNA polymerase binds to start transcription.

Operator

Region where repressor binds to inhibit transcription.

Structural genes

Genes that code for proteins in an operon.

Transacetylase

Enzyme in lactose operon that transfers acetyl group to another molecule

Repressor protein

Protein that inhibits transcription by binding to operator.

Inducer

Molecule that inactivates the repressor, allowing transcription.

Allolactose

Substrate that binds to repressor, enabling gene expression.

Catabolite repression

Inhibition of operon when glucose is present.

Growth rate

Speed of bacterial reproduction based on available sugars.

Lactase

Enzyme produced when lactose is available.

Lag period

Delay before lactose utilization after glucose depletion.

RNA polymerase

Enzyme that synthesizes RNA from DNA template.

Energy efficiency

Bacteria conserve resources by regulating gene expression.

Glycolysis enzymes

Constitutive genes involved in glucose metabolism.

E. coli

Bacterial model organism for studying operons.

Transcription

Process of copying DNA into RNA.

Translation

Process of synthesizing proteins from mRNA.