Question 1

Which of the following best explains why viruses are classified as nonliving microbes?

Accepted Answer

They lack the ability to reproduce independently outside a host cell.

Question 2

A scientist is studying a virus with a helical capsid and a lipid envelope. Which of the following statements about this virus is most likely true?

Accepted Answer

It acquires its envelope by budding from the host cell membrane.

Question 3

Which of the following best describes antigenic shift in influenza viruses?

Accepted Answer

A major genetic reassortment event that can lead to pandemics.

Question 4

A virus has a single-stranded negative-sense RNA genome. Which enzyme must it carry or encode to replicate in a host cell?

Accepted Answer

RNA-dependent RNA polymerase

Question 5

Which of the following is a correct statement about viral host range?

Accepted Answer

It refers to the collection of species that a virus can infect.

Question 6

A patient is diagnosed with a chronic viral infection that persists for years with slow progression of disease. Which virus is most likely responsible?

Accepted Answer

Human immunodeficiency virus (HIV)

Question 7

Which of the following best describes the function of the viral capsid?

Accepted Answer

It is a protein shell that packages and protects the viral genome.

Question 8

During the lytic replication pathway of a bacteriophage, what is the fate of the host bacterial cell?

Accepted Answer

It is lysed and killed as new bacteriophages are released.

Question 9

Which of the following is a key difference between enveloped and naked (nonenveloped) animal viruses during entry into host cells?

Accepted Answer

Enveloped viruses can enter through membrane fusion, while naked viruses enter by endocytosis.

Question 10

A virus is found to cause cancer by integrating its genome into the host cell's DNA and disrupting cell cycle regulation. What type of virus is this?

Accepted Answer

Oncogenic virus (oncovirus)

Question 11

Which of the following best explains why RNA viruses evolve faster than DNA viruses?

Accepted Answer

RNA polymerases lack proofreading capabilities, leading to higher mutation rates.

Question 12

A laboratory is using a plaque assay to quantify bacteriophages. What does each plaque on the agar plate represent?

Accepted Answer

A single bacteriophage that infected and lysed a bacterial cell.

Question 13

Which of the following steps is unique to the lysogenic replication pathway of temperate phages?

Accepted Answer

Integration of the phage genome into the host cell genome as a prophage.

Question 14

Which of the following is a correct statement about viral tropism?

Accepted Answer

It refers to the tissues or cell specificity of a virus.

Question 15

A virus with a double-stranded DNA genome must first perform which step before its genes can be expressed in a host cell?

Accepted Answer

Transcribe its DNA into mRNA using host RNA polymerases.

Question 16

Which of the following is a plausible reason why attenuated viral strains are used in vaccines?

Accepted Answer

They have limited infectivity and reduced ability to cause disease.

Question 17

Which of the following best describes the function of viral spikes (peplomers)?

Accepted Answer

They are glycoprotein extensions that help viruses attach and gain entry to host cells.

Question 18

A patient experiences periodic flare-ups of symptoms due to a latent viral infection. Which of the following viruses is most likely responsible?

Accepted Answer

Herpes simplex virus (HSV)

Question 19

Which of the following is a correct statement about the International Committee on Taxonomy of Viruses (ICTV)?

Accepted Answer

It provides criteria for naming and classifying viruses.

Question 20

Which of the following best explains why viruses require a host cell for replication?

Accepted Answer

They lack the cellular machinery needed to synthesize proteins and replicate their genome.

Comprehensive Study Notes on General Virus Characteristics and Replication (Microbiology)

Guida di studio - Domande di pratica

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