Regulation of Gene Expression Notes

Regulation of Gene Expression

Bacterial Gene Regulation

• Bacteria adjust their metabolism based on the availability of compounds in their environment.
• They can either synthesize a substance or halt its production based on need.
• Feedback inhibition is used for regulation.
• An operon, a DNA sequence, coordinates metabolic pathways.

Operon Structure and Function

• Genes coding for enzymes in a pathway (e.g., tryptophan synthesis) are clustered on the bacterial chromosome.
• A single promoter controls all these genes. RNA polymerase binds to the promoter and transcribes a long mRNA.
• Ribosomes then translate the individual enzymes from this mRNA, each having its own start and stop codon.

The Tryptophan (trp) Operon

• Transcription is controlled by the operator, a DNA sequence in the promoter region acting as an on/off switch.
• The trp operon is typically