LAC Operon and Bacterial Metabolism

Vocabulary flashcards detailing the components and regulatory mechanisms of the LAC operon as presented in the lecture notes.

LAC Operon

A genetic system found in bacteria like E. coli that regulates the production of enzymes needed to digest lactose.

Glucose

The preferred energy source for E. coli; it is digested before the cell utilizes lactose.

Lactose

A secondary energy source that E. coli will digest only if no glucose is available.

Regulator gene

A specific DNA sequence that controls the operon, often by producing a repressor molecule.

Promoter

The region on the DNA where RNA polymerase binds to begin the process of transcription.

Operator

The segment of DNA that acts as a switch, where a repressor can bind to block RNA polymerase.

Structural genes

The portion of the LAC operon that contains the genetic code for Enzyme 1, Enzyme 2, and Enzyme 3.

RNA polymerase

The enzyme that moves along the DNA to transcribe structural genes into mRNA.

Repressor ($E$)

A molecule that binds to the operator to prevent transcription when the operon is turned off.

Transcription

The process of copying a segment of DNA into mRNA.

Translation

The process by which mRNA is decoded to produce specific enzymes.

mRNA

The messenger RNA molecule created during transcription that carries instructions for protein synthesis.

Enzyme 1, Enzyme 2, and Enzyme 3

The three specific proteins produced by the structural genes of the LAC operon to facilitate lactose digestion.