Gene Regulation in Prokaryotes

What are the two ways accessory proteins can regulate the promoter site in prokaryotes?

• Positive regulation by activators

• Negative regulation by repressors

What are the three ways to control the transcription of an operon in prokaryotic cells?

• Repressive control

• Activator control

• Inducible control

What is the function of the lac repressor in the lac operon?

• Represses transcription

• Activates transcription

What conditions must be met for E. coli to express the lac operon efficiently?

• Lactose is available

• Glucose is not available

What happens to the lac repressor when lactose is present?

• It binds to the operator

• It loses its ability to bind DNA

What is catabolite repression of the lac operon?

• A mechanism that prevents lactose use when glucose is available

• A mechanism that promotes lactose use when glucose is available

What is the role of catabolite activator protein (CAP) in the lac operon?

• It binds to the promoter to promote transcription

• It binds to the operator to inhibit transcription

What are the three elements proposed in the operon model?

• Structural genes

• Operator site

• Regulator gene

What is the function of the structural genes in the lac operon?

• They encode proteins involved in lactose metabolism

• They regulate transcription

What is the significance of the CAP binding site in the lac operon?

• It promotes transcription when bound by CAP

• It inhibits transcription when bound by CAP