$$\text{A in DNA} \rightarrow \text{U in RNA}$$

$$\text{RNA is synthesized 5' \rightarrow 3'}$$

$$\text{Gene expression} \propto \text{mRNA half-life}$$

Question 1

Which region of a bacterial gene is primarily responsible for determining when and how often transcription occurs?

Accepted Answer

Promoter

Question 2

What is the function of the sigma factor in bacterial transcription?

Accepted Answer

It recognizes the promoter sequence and initiates DNA strand separation

Question 3

If the -10 region of a bacterial promoter is mutated from TATAAT to GCCGGGCC, what is the most likely effect on transcription?

Accepted Answer

Transcription would decrease

Question 4

Which equation best represents the base pairing during transcription?

Accepted Answer

$$	ext{A in DNA} ightarrow 	ext{U in RNA}$$

Question 5

Which of the following is NOT a function of RNases in bacteria?

Accepted Answer

Initiation of transcription

Question 6

Which type of RNA is most abundant and stable in bacterial cells?

Accepted Answer

rRNA

Question 7

What is the primary difference between bacterial and eukaryotic RNA polymerases?

Accepted Answer

Bacterial RNA polymerase is made of fewer subunits than eukaryotic RNA polymerase

Question 8

Which sigma factor in Escherichia coli is primarily responsible for the heat shock response?

Accepted Answer

RpoH ($$\$$sigma^{32}$$)

Question 9

Which of the following best describes a polycistronic RNA?

Accepted Answer

An RNA molecule that contains multiple open reading frames and can encode several proteins

Question 10

Which mechanism is responsible for Rho-independent transcription termination in bacteria?

Accepted Answer

Formation of a GC-rich stem-loop followed by a stretch of U's in the RNA

Question 11

A mutation in the operator region of a gene would most likely affect:

Accepted Answer

The regulation of gene expression by repressor or activator proteins

Question 12

Which of the following equations correctly represents the directionality of transcription?

Accepted Answer

$$	ext{RNA is synthesized 5' ightarrow 3'}$$

Question 13

Which of the following is a plausible consequence of a mutation that prevents the formation of a stem-loop structure in the RNA near the terminator?

Accepted Answer

Transcription would fail to terminate properly, resulting in longer transcripts

Question 14

Which equation best describes the relationship between mRNA stability and gene expression in bacteria?

Accepted Answer

$$	ext{Gene expression} \propto 	ext{mRNA half-life}$$

Question 15

Which of the following statements about bacterial mRNA processing is correct?

Accepted Answer

Bacterial mRNAs are not spliced, capped, or polyadenylated

Question 16

Which of the following is a direct result of the activity of Rho helicase during transcription termination?

Accepted Answer

Disruption of the RNA:DNA hybrid, leading to release of RNA polymerase

Question 17

Which of the following best explains why mRNA is less stable than rRNA or tRNA in bacteria?

Accepted Answer

mRNA is rapidly degraded by RNases to allow quick changes in gene expression

Question 18

Which of the following equations represents the base pairing in a GC-rich stem-loop structure?

Accepted Answer

$$	ext{G} \equiv 	ext{C}$$

Question 19

Which of the following is a multi-step process that occurs during transcription in bacteria?

Accepted Answer

Sigma factor binds promoter, RNA polymerase separates DNA strands, rNTPs are incorporated, sigma factor dissociates

Question 20

Which of the following best describes the role of the ribosome binding site (RBS) in bacterial gene expression?

Accepted Answer

It marks the site for the ribosome to start translation

Transcription and Gene Structure in Bacteria: Mechanisms and Regulation

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