Gene Regulation

What specific sugar does E.coli break down when milk is consumed?

• Glucose

• Sucrose

• Lactose

• Fructose

In the context of gene regulation, what is a segment of DNA typically found upstream of a gene that serves as a binding site for regulatory proteins?

• Regulatory gene

• Regulatory protein

• Regulatory sequence

• Structural gene

What is the correct general flow of genetic information in gene expression?

• Protein → mRNA → DNA

• DNA → Protein → mRNA

• mRNA → DNA → Protein

• DNA → mRNA → Protein

In the lac operon, which region of DNA is located between the promoter and the structural genes and functions as an on/off switch for transcription?

• Regulatory gene

• Operator

• TATA Box

• Activator

In the lac operon, what is the primary function of the repressor protein when lactose is absent?

• It binds to the promoter, initiating transcription.

• It binds to the operator, blocking RNA polymerase from transcribing the genes.

• It binds to the lacZ gene, activating enzyme production.

• It changes shape to allow lactose to bind.

When lactose is present in the environment of a bacterium with a lac operon, what is the direct effect on the repressor protein?

• The repressor binds more tightly to the operator.

• The repressor detaches from the operator and changes shape.

• The repressor is degraded by enzymes.

• The repressor recruits RNA polymerase to the promoter.

How does the presence of tryptophan regulate the trp operon in bacteria?

• Tryptophan binds to the repressor, preventing it from attaching to the operator.

• Tryptophan binds to the promoter, initiating the synthesis of more tryptophan.

• Tryptophan binds to the repressor, enabling it to block RNA polymerase from transcribing the genes.

• Tryptophan directly activates RNA polymerase to produce enzymes for its breakdown.

Which of the following best describes a key difference in gene regulation between prokaryotes and eukaryotes?

• Prokaryotes use operons for coordinated gene expression, while eukaryotes rely on transcription factors and DNA folding.

• Eukaryotes primarily use repressors to block gene transcription, whereas prokaryotes use activators.

• Prokaryotic gene regulation is more complex due to the presence of a nucleus.

• Both prokaryotes and eukaryotes utilize identical operon structures for gene control.