Question 1

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

Accepted Answer

They lack cellular structure and cannot carry out metabolic processes independently.

Question 2

A scientist is comparing a virus to a prokaryotic cell. Which of the following is a feature unique to viruses and not found in prokaryotic or eukaryotic cells?

Accepted Answer

A protein capsid surrounding the genetic material

Question 3

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes can be composed of either DNA or RNA, which may be single- or double-stranded.

Question 4

A virus with a single-stranded positive-sense RNA genome ($$ssRNA^+) $$infects a host cell. Which process must occur for this virus to produce viral proteins?

Accepted Answer

The $$ssRNA^+$$ genome is directly used as mRNA for translation.

Question 5

Why do RNA viruses tend to evolve more rapidly than DNA viruses?

Accepted Answer

RNA viruses have higher mutation rates due to lack of proofreading by RNA-dependent RNA polymerases.

Question 6

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

Accepted Answer

A sudden major change in the viral genome due to reassortment of gene segments.

Question 7

A bacteriophage infects a bacterial cell and integrates its genome into the host chromosome, remaining dormant for several generations. This process is known as:

Accepted Answer

Lysogenic replication

Question 8

Phage conversion is medically important because:

Accepted Answer

It can result in bacteria acquiring new virulence factors from prophage genes.

Question 9

Which step is unique to animal virus replication compared to bacteriophage replication?

Accepted Answer

Uncoating of the viral capsid after entry into the host cell

Question 10

How do enveloped animal viruses typically exit the host cell?

Accepted Answer

By budding from the host cell membrane, acquiring their envelope in the process

Question 11

A patient is diagnosed with a persistent latent viral infection. Which of the following best describes this type of infection?

Accepted Answer

The virus remains dormant in the host cell and can reactivate later, causing symptoms.

Question 12

Which of the following viruses is known to be oncogenic and associated with human cancer?

Accepted Answer

Human papillomavirus (HPV), which can cause cervical cancer

Question 13

Which statement best describes prions?

Accepted Answer

They are altered forms of normal proteins that can induce misfolding in other proteins.

Question 14

What is the typical outcome once symptoms of prion disease develop in humans?

Accepted Answer

Progressive neurodegeneration leading to death

Question 15

Which prion disease affects sheep and is characterized by intense itching and loss of coordination?

Accepted Answer

Scrapie

Question 16

A hunter in North America is concerned about prion diseases in deer and elk. Which disease should they be most aware of?

Accepted Answer

Chronic wasting disease

Question 17

Which of the following is a human prion disease that can be transmitted through contaminated surgical instruments?

Accepted Answer

Creutzfeldt-Jakob disease (CJD)

Question 18

A new strain of influenza emerges due to the reassortment of gene segments from two different viruses infecting the same host. This is an example of:

Accepted Answer

Antigenic shift

Question 19

Which of the following best defines the term 'host range' in virology?

Accepted Answer

The spectrum of host species or cell types a virus can infect

Question 20

A retrovirus uses reverse transcriptase to convert its RNA genome into DNA. Which equation best represents this process?

Accepted Answer

$$RNA \xrightarrow{	ext{reverse transcriptase}} DNA$$

Viruses and Prions: Structure, Replication, and Pathogenesis

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