Question 1

Which of the following best describes the main difference between the lytic and lysogenic cycles of a bacteriophage?

Accepted Answer

The lytic cycle leads to destruction of the host cell, while the lysogenic cycle allows the viral genome to persist in the host without killing it.

Question 2

Which enzyme is responsible for copying the viral RNA genome into DNA in retroviruses?

Accepted Answer

Reverse transcriptase

Question 3

A virus with a segmented genome is more likely to undergo which evolutionary process, leading to major antigenic changes?

Accepted Answer

Antigenic shift

Question 4

Which of the following statements about transformation in bacteria is CORRECT?

Accepted Answer

Transformation involves uptake of naked DNA from the environment.

Question 5

Which of the following is a plausible reason why DNA polymerase cannot replicate the very ends of linear chromosomes?

Accepted Answer

DNA polymerase requires a primer and cannot fill in the gap left after primer removal at the 5' end.

Question 6

Which of the following best describes conjugation in bacteria?

Accepted Answer

Transfer of DNA from a donor to a recipient via a pilus.

Question 7

Which of the following is a key feature of +ssRNA viruses?

Accepted Answer

Their genome can serve directly as mRNA for translation.

Question 8

Which of the following is TRUE regarding antigenic drift?

Accepted Answer

It is caused by accumulation of point mutations in viral genes.

Question 9

Which of the following is NOT a target for antimicrobial drugs?

Accepted Answer

Viral envelope proteins

Question 10

Which of the following statements about transduction is CORRECT?

Accepted Answer

Transduction is mediated by bacteriophages transferring DNA between bacteria.

Question 11

Which of the following best describes the eclipse period in the viral life cycle?

Accepted Answer

The period after entry but before new virions are assembled.

Question 12

Which of the following is a characteristic of retroviruses?

Accepted Answer

They use reverse transcriptase to synthesize DNA from an RNA template.

Question 13

Which of the following is an example of vertical gene transfer?

Accepted Answer

Transfer of DNA from parent to offspring during cell division.

Question 14

Which of the following is TRUE about the ribosome binding site (RBS) in prokaryotes?

Accepted Answer

It is a sequence in mRNA that helps recruit the ribosome for translation.

Question 15

Which of the following best describes the process of horizontal gene transfer?

Accepted Answer

Transfer of genetic material between unrelated organisms.

Question 16

Which of the following is a function of the bacterial capsule?

Accepted Answer

It protects bacteria from phagocytosis.

Question 17

Which of the following is a plausible outcome if a virus with a segmented genome infects a cell already infected by a related virus?

Accepted Answer

The viruses may reassort their genome segments, leading to antigenic shift.

Question 18

Which of the following is a key difference between +ssRNA and -ssRNA viruses?

Accepted Answer

-ssRNA viruses must carry an RNA-dependent RNA polymerase in the virion.

Question 19

Which of the following is TRUE regarding the lysogenic cycle of a bacteriophage?

Accepted Answer

The phage genome is integrated into the host chromosome as a prophage.

Microbiology Exam Study Guide: Viral Life Cycles, Genetic Exchange, and Antigenic Variation

Study Guide - Practice Questions