Operons Quizziz

A protein that binds to the operator and blocks the RNA polymerase

• regulator
• repressor
• activator
• corepressor

What is the role of operons in prokaryote gene expression?

• It makes the genes prokaryotes be turned on
• It accounts for the regulation of gene activity in response to the needs of the cells
• To make DNA for the gene
• To make the gene turn of and off

Operons are found in the cells of which of the following types of organisms?

• prokaryotes (bacteria)
• eukaryotes (plant and animals)
• animals only
• viruses

What does the inducer molecule do in an inducible operon?

• it binds to the repressor protein allowing transcription to occur
• it binds to the promoter allowing transcription to occur
• it binds to the operator and stops transcription
• it binds to the repressor and stops transcription

Which type of operon is shown in the image?

• inducible operon
• repressible operon
• positive control operon
• can't determine this from the image

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

• inducible operon

• repressible operon

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

For a repressible operon to be transcribed, which of the following must be true?

• A corepressor must be present.
• RNA polymerase and the active repressor must be present.
• RNA polymerase must bind to the promoter, and the repressor must be inactive.
• RNA polymerase cannot be present, and the repressor must be inactive.

Which of the following statements regarding the trp operon is true?

• The operator region produces the mRNA that codes for the repressor.

• The regulatory gene is not transcribed in the presence of the repressor.

• Repressor proteins are inactivated by the presence of the repressor. .

• The trp operon is always activated unless deactivated by a repressor

Tags

NGSS.HS-LS1-3

In the lac operon, the genes within the operon will be expressed if:

• lactose is absent in the cell
• galactose is present in the cell
• lactose is present in the cell
• glucose is absent in the cell