Question 1

Which of the following best explains why transcription and translation are coupled in bacteria?

Accepted Answer

Because bacterial cells lack a nuclear membrane, allowing ribosomes to access mRNA as soon as it is synthesized.

Question 2

A bacterial operon is best described as:

Accepted Answer

A cluster of genes transcribed together from a single promoter, producing a polycistronic mRNA.

Question 3

Which feature of bacterial genomes allows for rapid adaptation to environmental changes?

Accepted Answer

Multiple rounds of chromosome replication can occur simultaneously in dividing cells.

Question 4

What is the primary function of plasmids in bacteria?

Accepted Answer

To confer advantages such as antibiotic resistance or survival in specific environments.

Question 5

Which of the following is NOT a criterion used to classify viruses into families?

Accepted Answer

Ribosomal RNA sequence similarity

Question 6

A plasmid that carries the gene 'Tet' provides bacteria with resistance to which antibiotic?

Accepted Answer

Tetracycline

Question 7

Which of the following statements about bacterial DNA is correct?

Accepted Answer

Bacterial genomes are efficient, with most DNA coding for genes and little non-coding DNA.

Question 8

What is the role of the sigma ($$\sigma) $$factor in bacterial transcription?

Accepted Answer

It recognizes promoter sequences and initiates binding of RNA polymerase to DNA.

Question 9

Which process is responsible for the synthesis of a polypeptide based on an mRNA template?

Accepted Answer

Translation

Question 10

A bacterial cell is exposed to tetracycline. Which genetic element would most likely allow it to survive?

Accepted Answer

A plasmid carrying the Tet gene

Question 11

Which of the following best describes rolling circle replication in plasmids?

Accepted Answer

Replication starts at a specific site and proceeds unidirectionally, displacing a single strand that can be transferred to another cell.

Question 12

Which RNA type is directly involved in carrying amino acids during protein synthesis?

Accepted Answer

tRNA

Question 13

In bacteria, which sequence is most commonly recognized by the sigma factor to initiate transcription?

Accepted Answer

Pribnow box ($$-10$$ sequence)

Question 14

Which of the following is a consequence of the weak U-A base pairing during rho-independent transcription termination?

Accepted Answer

It allows the RNA transcript to easily dissociate from the DNA template, ending transcription.

Question 15

Which phase of transcription involves the extension of the RNA chain by RNA polymerase?

Accepted Answer

Elongation

Question 16

A mutation in the -35 sequence of a bacterial promoter would most likely affect:

Accepted Answer

The ability of the sigma factor to recognize and bind the promoter.

Question 17

Which of the following best explains why bacteria can rapidly increase in population size?

Accepted Answer

They can initiate multiple rounds of chromosome replication before cell division is complete.

Question 18

Which of the following is NOT a function of small RNAs in bacteria?

Accepted Answer

Carrying amino acids during translation

Question 19

Which equation correctly represents the base pairing between DNA and RNA during transcription?

Accepted Answer

$$	ext{DNA:}~A \longleftrightarrow 	ext{RNA:}~U$$

Question 20

Which of the following best describes a polycistronic mRNA?

Accepted Answer

An mRNA that encodes multiple proteins, each from a different open reading frame (ORF).

Bacterial Genes, Genomes, and Gene Expression: Structure, Function, and Adaptation

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