Question 1

Which of the following structural differences distinguishes RNA from DNA?

Accepted Answer

RNA contains ribose as its sugar and uracil instead of thymine.

Question 2

During transcription in E. coli, which region of the DNA is recognized by RNA polymerase to initiate transcription?

Accepted Answer

The -35 and -10 promoter regions.

Question 3

Which enzyme is primarily responsible for the cleavage of mRNA during decay in bacteria?

Accepted Answer

RNase E

Question 4

What is the function of the 'scrunching' mechanism during abortive initiation in E. coli transcription?

Accepted Answer

It allows the RNA polymerase to synthesize short RNA fragments before escaping the promoter.

Question 5

Which of the following best describes the direction of RNA synthesis during transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 6

A mutation in the -10 region of a bacterial promoter is most likely to affect which process?

Accepted Answer

Binding of RNA polymerase and initiation of transcription

Question 7

Which of the following is a feature of rho-independent transcription termination in E. coli?

Accepted Answer

Formation of a hairpin structure followed by a string of uracils in the RNA.

Question 8

In the process of mRNA decay in bacteria, which sequence of events is correct?

Accepted Answer

5' processing, internal cleavage, 3' exonuclease decay

Question 9

Which of the following statements about the template and nontemplate strands during transcription is correct?

Accepted Answer

The template strand is complementary to the RNA product.

Question 10

Which of the following equations correctly represents the addition of a nucleotide during RNA synthesis?

Accepted Answer

$$\mathrm{NTP} + (RNA)_{n} \rightarrow (RNA)_{n+1} + \mathrm{PP_i}$$

Question 11

Which of the following is NOT a step in the bacterial mRNA life cycle as depicted in the provided diagram?

Accepted Answer

Replication

Question 12

A researcher observes that a bacterial mRNA is rapidly degraded after internal cleavage. Which enzyme is most likely responsible for this process?

Accepted Answer

RNase E

Question 13

Which of the following best explains why uracil is present in RNA but not in DNA?

Accepted Answer

Uracil is less stable and more prone to mutation, so it is excluded from DNA.

Question 14

Which process is directly affected if the catalytic core of RNA polymerase is mutated?

Accepted Answer

Transcription elongation

Question 15

In a bacterial cell, what would be the consequence of a nonfunctional 3' exonuclease during mRNA decay?

Accepted Answer

Accumulation of partially degraded mRNA fragments.

Question 16

Which of the following is a correct sequence of events for transcription initiation in E. coli?

Accepted Answer

RNA polymerase binds to the promoter, DNA unwinds, abortive initiation occurs, elongation begins.

Question 17

Which of the following is a real-world application of understanding mRNA decay mechanisms in bacteria?

Accepted Answer

Designing antibiotics that target RNase E to prevent bacterial growth.

Question 18

Which of the following statements about the role of sigma factor in bacterial transcription is correct?

Accepted Answer

Sigma factor is required for promoter recognition and initiation of transcription.

Question 19

A mutation in the Rut site of a bacterial gene would most likely affect which process?

Accepted Answer

Rho-dependent transcription termination

Question 20

Which of the following best describes the role of pyrophosphohydrolase in mRNA decay?

Accepted Answer

It removes pyrophosphate from the 5' end, facilitating mRNA degradation.

RNA Transcription: Structure, Mechanism, and Decay in Bacteria

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