Question 1

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental and one daughter strand.

Question 2

A mutation that results in the insertion or deletion of a single nucleotide in a coding region is most likely to cause which of the following?

Accepted Answer

A frameshift mutation

Question 3

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids replicate independently of the chromosome.

Question 4

During prokaryotic DNA replication, which enzyme is responsible for removing supercoils ahead of the replication fork?

Accepted Answer

Gyrase

Question 5

Which of the following is a function of DNA methylation in bacteria?

Accepted Answer

Protection against viral infection

Question 6

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized in short fragments.

Question 7

Which of the following is NOT a step in prokaryotic transcription?

Accepted Answer

Splicing

Question 8

In eukaryotes, which of the following modifications occurs to pre-mRNA before it is translated?

Accepted Answer

All of the above

Question 9

Which of the following is a correct statement about the lac operon in E. coli?

Accepted Answer

It is an inducible operon activated by the presence of lactose.

Question 10

Which of the following best describes generalized transduction?

Accepted Answer

A bacteriophage transfers random donor DNA segments to a recipient cell.

Question 11

A scientist exposes a bacterial culture to UV light, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to directly reverse this damage?

Accepted Answer

Photoreactivation (light repair)

Question 12

Which of the following is a characteristic of an Hfr cell in bacterial conjugation?

Accepted Answer

It can transfer chromosomal genes to a recipient cell.

Question 13

Which of the following is the correct sequence of events in the central dogma of molecular biology?

Accepted Answer

DNA → RNA → protein

Question 14

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 15

Which of the following is TRUE regarding transposons?

Accepted Answer

They are segments of DNA that can move from one location to another within a genome.

Question 16

Which of the following best explains why mutagens increase the frequency of mutations?

Accepted Answer

They cause changes in the DNA sequence during replication or repair.

Question 17

Which of the following is a role of regulatory RNAs such as microRNAs (miRNAs) in genetic expression?

Accepted Answer

They bind to complementary mRNA and inhibit its translation.

Question 18

A bacterial cell is exposed to a nucleotide analog. Which of the following outcomes is most likely?

Accepted Answer

Base-pair substitutions and missense mutations

Question 19

Which of the following is a key difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

Eukaryotic mRNA is processed by capping, polyadenylation, and splicing before translation.

Question 20

Which of the following best describes the function of the operator in a prokaryotic operon?

Accepted Answer

It is a regulatory sequence where a repressor protein can bind to block transcription.

Microbial Genetics: Structure, Replication, and Expression

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