Question 1

Which of the following best describes an operon in prokaryotic gene regulation?

Accepted Answer

A group of two or more genes transcribed into a single mRNA under the control of a single promoter

Question 2

In the negative control of the arginine operon, what happens when arginine is present in high concentrations?

Accepted Answer

The repressor binds to the operator with arginine as a corepressor, blocking transcription

Question 3

Which of the following statements about DNA binding proteins in prokaryotes is correct?

Accepted Answer

They recognize specific nucleotide sequences, often involving inverted repeats

Question 4

A mutation in the gene encoding the sensor kinase of a two-component regulatory system would most likely result in:

Accepted Answer

Inability to sense environmental signals and improper regulation of target genes

Question 5

Which of the following best explains the function of quorum sensing in bacteria?

Accepted Answer

It allows bacteria to sense and respond to population density by producing and detecting signaling molecules

Question 6

What is the main difference between positive and negative control of transcription in prokaryotes?

Accepted Answer

Positive control involves activator proteins that enhance transcription, while negative control involves repressor proteins that inhibit transcription

Question 7

Which of the following is a correct statement about noncoding RNA?

Accepted Answer

Noncoding RNA includes tRNA, rRNA, and small regulatory RNAs that are not translated into protein

Question 8

A patient is diagnosed with hepatitis D. Which of the following is necessary for the hepatitis D virus to cause infection?

Accepted Answer

The presence of hepatitis B virus in the host

Question 9

Which of the following mechanisms is NOT a way that small regulatory RNAs (sRNAs) can alter gene expression?

Accepted Answer

Directly catalyzing the synthesis of proteins from mRNA

Question 10

Which of the following best describes the role of hemagglutinin in influenza virus infection?

Accepted Answer

It binds to epithelial cell surface receptors, facilitating viral entry

Question 11

A researcher is studying a bacterial operon that is only transcribed when a specific activator protein binds to the DNA in the presence of a small molecule. This is an example of:

Accepted Answer

Positive control with an inducer

Question 12

Which of the following statements about the regulation of transcription in Archaea is correct?

Accepted Answer

It is more similar to bacterial regulation than to eukaryotic regulation

Question 13

What is the function of a corepressor in the regulation of gene expression?

Accepted Answer

It binds to a repressor protein, enabling the repressor to bind DNA and block transcription

Question 14

Which of the following best explains why influenza virus is unique among viruses?

Accepted Answer

It is the only virus capable of genetic shift, allowing for major changes in its genome

Question 15

A bacterial cell is exposed to a new environment and must rapidly alter gene expression. Which regulatory system is most likely to be involved in sensing and responding to this change?

Accepted Answer

Two-component regulatory system involving a sensor kinase and a response regulator

Question 16

Which of the following is a plausible consequence of a mutation that prevents the binding of a repressor protein to the operator in the lac operon?

Accepted Answer

The operon will be constitutively expressed, even in the absence of lactose

Question 17

Which of the following equations best represents the relationship between the rate of mRNA degradation ($k_{deg}$), mRNA concentration ($[mRNA]$), and the rate of change of mRNA over time ($\frac{d[mRNA]}{dt}$)?

Accepted Answer

$\frac{d[mRNA]}{dt} = -k_{deg} \cdot [mRNA]$

Question 18

Which of the following best describes the effect of a neuraminidase inhibitor on influenza virus infection?

Accepted Answer

It does not stop infection but prevents the spread of the virus in a systematic way

Question 19

Which of the following is a real-world example of allosteric inhibition in bacterial metabolism?

Accepted Answer

Arginine binding to the repressor protein, changing its shape and allowing it to bind the operator

Microbial Gene Regulation and Viral Pathogenesis: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards