Quick 10Q: Operons

Which of the following describes an operon that is inactive and becomes activated by a molecule binding to the repressor?

• inducible operon

• repressible operon

Which of the following describes an operon that is active and becomes inactivated by a molecule binding to the repressor?

• inducible operon

• repressible operon

The lac operon is an example of an inducible operon. Which of the following describes the process that occurs when lactose is present?

• The lactose binds to the repressor which inactivates it and the repressor binds to the operator to turn translation on.

• The lactose binds to the repressor which activates it and the repressor releases from the operator to turn translation on.

• The lactose binds to the repressor which inactivates it and the repressor releases from the operator to turn translation on.

• The lactose binds to the repressor which activates it and the repressor binds to the operator to turn translation on.

The trp operon is an example of an repressible operon. Which of the following describes the process that occurs when tryptophan is present?

• The tryptophan binds to the repressor which inactivates it and the repressor binds to the operator to turn translation off.

• The tryptophan binds to the repressor which activates it and the repressor releases from the operator to turn translation off.

• The tryptophan binds to the repressor which inactivates it and the repressor releases from the operator to turn translation off.

• The tryptophan binds to the repressor which activates it and the repressor binds to the operator to turn translation off.

In the trp operon, the tryptophan binds to the repressor. Which of the following is the term used to describe this molecule?

• inducer

• corepressor

• enhancer

• CAP

In the lac operon, the allolactose binds to the repressor. Which of the following is the term used to describe this molecule?

• inducer

• corepressor

• enhancer

• CAP

Which of the following describes the type of pathway that an inducible operon controls?

• anabolic pathway

• catabolic pathway

Which of the following describes the type of pathway that a repressible operon controls?

• anabolic pathway

• catabolic pathway

Which of the following describes the function of the operator in the operon?

• site of repressor binding for on/off switch

• site of RNA polymerase binding for transcription

• site of promoter binding for RNA synthesis

• site of inducer binding for activation of pathway

Which of the following describes the function of the promoter in the operon?

• site of repressor binding for on/off switch

• site of RNA polymerase binding for transcription

• site of operator binding for RNA synthesis

• site of inducer binding for activation of pathway