Control of Gene Expression in Prokaryotes

What is an operon in prokaryotic cells?

• A group of genes regulated together with one switch

• A single gene that controls all cell functions

• A protein that binds to DNA

• A molecule that induces gene expression

What is the function of the repressor protein shown in the diagram?

• The repressor protein binds to the operator to prevent RNA polymerase from transcribing the genes.

• The repressor protein binds to the promoter to initiate transcription.

• The repressor protein acts as an enzyme to break down mRNA.

• The repressor protein helps ribosomes attach to the mRNA.

Tags

NGSS.HS-LS1-1

In prokaryotic cells, the group of genes regulated together with the sections of DNA that control them is called an _______.

• operon

• plasmid

• chromosome

• promoter

In prokaryotic cells, RNA polymerase binds to the operator to start transcription.

• True

• False

What type of operon is illustrated in Model 1?

• Inducible operon

• Repressible operon

• Constitutive operon

• Attenuated operon

In Model 1, where on the DNA strand does RNA polymerase bind to start transcription?

• At the promoter region

• At the terminator region

• At the start codon

• At the stop codon

4. The RNA polymerase in Model 1 is moving in which direction?

• 5' to 3' direction

• 3' to 5' direction

• Both directions

• It is stationary

What protein does the regulatory gene in Model 1 produce?

• Repressor protein

• Enzyme

• Structural protein

• Activator protein

Tags

NGSS.HS-LS1-1

7b. Refer to diagram A in Model 1. The protein binds to which section of the operon?

• Promoter

• Operator

• Structural gene

• Terminator

7c. Refer to diagram A in Model 1. Transcription is not occurring in diagram A because:

• The promoter region is blocked by a repressor protein.

• RNA polymerase is actively transcribing the gene.

• The DNA is unwound and accessible.

• Transcription factors are bound to the enhancer region.