Question 1

Which of the following statements best explains why viruses are considered obligate intracellular parasites?

Accepted Answer

They require a living host cell to replicate and carry out metabolic processes.

Question 2

A scientist isolates a virus with a helical capsid, an RNA genome, and an envelope with glycoprotein spikes. According to the Baltimore classification, which group does this virus most likely belong to?

Accepted Answer

Group IV: (+)ssRNA viruses

Question 3

Which of the following best describes the function of glycoprotein spikes on enveloped viruses?

Accepted Answer

They facilitate attachment to specific host cell receptors for entry.

Question 4

Which virus was the first to be discovered and visualized by electron microscopy?

Accepted Answer

Tobacco mosaic virus (TMV)

Question 5

A patient is infected with a virus that has a double-stranded DNA genome and an icosahedral capsid. Which of the following viruses fits this description?

Accepted Answer

Adenovirus

Question 6

Which of the following statements about viral genomes is correct?

Accepted Answer

A viral genome can be either DNA or RNA, but never both in the same virion.

Question 7

Which of the following is NOT a function of the viral capsid?

Accepted Answer

Synthesizing viral proteins

Question 8

A virus is described as having a segmented, negative-sense single-stranded RNA genome. According to the Baltimore classification, which group does it belong to?

Accepted Answer

Group V: (–)ssRNA viruses

Question 9

Which of the following best describes the difference between a virion and a virus?

Accepted Answer

A virion is the complete, infectious particle outside a host cell; a virus can refer to the virion, the virus inside a cell, or integrated viral genetic material.

Question 10

Which of the following is a real-world application of viruses in medicine?

Accepted Answer

Using bacteriophages to treat bacterial infections resistant to antibiotics

Question 11

Which of the following statements about the Baltimore classification system is correct?

Accepted Answer

It groups viruses by their type of genetic material and mechanism of mRNA synthesis.

Question 12

A virus with a lipid envelope is generally:

Accepted Answer

Less stable outside the host cell compared to non-enveloped viruses

Question 13

Which of the following is the correct hierarchical order for virus taxonomy from highest to lowest?

Accepted Answer

Order, Family, Genus, Species

Question 14

Which of the following best describes a virome?

Accepted Answer

The total collection of viruses present in a particular environment or organism

Question 15

A patient presents with lesions on the skin and is diagnosed with a viral infection. Which of the following statements about the human skin virome is most accurate?

Accepted Answer

Viral communities on the skin may influence both healthy and disease states.

Question 16

Which of the following is a plausible reason why the International Committee on Taxonomy of Viruses (ICTV) standardizes virus nomenclature?

Accepted Answer

To ensure consistency and clarity in scientific communication

Question 17

Which of the following best describes the structure of a bacteriophage as seen in the provided images?

Accepted Answer

Icosahedral head, helical tail, and tail fibers

Question 18

A virus is found to have a capsid made of repeating protein subunits. What are these subunits called?

Accepted Answer

Capsomeres

Question 19

Which of the following is a multi-step process that all viruses must complete to replicate within a host cell?

Accepted Answer

Attachment, entry, replication, assembly, and release

Question 20

A newly discovered virus has a helical capsid, RNA genome, and an outer lipid layer with spike proteins. Predict its likely mode of entry into host cells and discuss how its architecture might influence vaccine development.

Accepted Answer

It likely enters by membrane fusion mediated by spike proteins; spike proteins are key targets for vaccine development.

Viruses: Structure, Classification, and Impact in Microbiology

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