Operon Model Quiz

What is an operon in prokaryotic cells?

• A) A single gene that controls several other genes

• B) A group of related genes grouped together with one switch

• C) A type of prokaryotic cell

• D) A protein that regulates gene expression

What is the role of the repressor protein in an inducible operon model?

• A) It binds to the promoter to initiate transcription

• B) It binds to the operator to block transcription

• C) It serves as an inducer molecule to activate transcription

• D) It attaches to the terminator to end transcription

In Diagram B, what happens when an inducer molecule interacts with the repressor protein?

• A) The repressor protein becomes active and binds to the operator

• B) The repressor protein remains inactive and transcription is blocked

• C) The repressor protein becomes inactive and transcription is initiated

• D) The inducer molecule acts as a promoter for gene expression

What is the function of RNA polymerase in the operon model shown in Diagram A?

• A) It represses gene expression by binding to the operator

• B) It terminates transcription by binding to the terminator

• C) It synthesizes mRNA by transcribing genes X, Y, and Z

• D) It activates the repressor protein to prevent gene expression

Which components are directly involved in the regulation of gene expression in the inducible operon model shown in Diagram B?

• A) Promoter, Operator, and Terminator

• B) Regulatory Gene, Repressor Protein, and Inducer Molecule

• C) RNA Polymerase, mRNA, and Protein X

• D) Gene X, Gene Y, and Gene Z

Where on the DNA strand does RNA polymerase bind to start transcription, the promoter, the operator or the terminator?

• Promoter

• Operator

• Terminator

• None of the above

Which direction is the RNA polymerase moving in Model 1?

• Left to right

• Right to left

• Upwards

• Downwards

In which diagram of Model 1 is transcription and translation occurring successfully, diagram A or diagram B? Justify your answer with evidence from Model 1.

• Diagram A, because RNA polymerase is present

• Diagram B, because RNA polymerase is present and moving along the DNA

• Diagram A, because the regulatory gene is not producing a protein

• Diagram B, because the regulatory gene is producing a protein

Match the purpose with each of these sections in the operon in terms of gene transcription: Promoter, Operator, Terminator.

• Promoter - Spot where transcription begins, Operator - On/Off switch, Terminator - Spot where transcription ends

• Promoter - On/Off switch, Operator - Spot where transcription ends, Terminator - Spot where transcription begins

• Promoter - Spot where transcription ends, Operator - Spot where transcription begins, Terminator - On/Off switch

• Promoter - Spot where transcription begins, Operator - Spot where transcription ends, Terminator - On/Off switch

To what section of the operon does this protein bind?

• Promoter

• Operator

• Terminator

• Regulatory gene