Question 1

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

Accepted Answer

They can only replicate by hijacking the metabolic machinery of a living host cell.

Question 2

A scientist discovers a new virus with a rod-shaped capsid, an RNA genome, and no envelope. According to the Baltimore classification, which group is this virus most likely to 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, enabling viral entry.

Question 4

A patient presents with a viral infection that is resistant to standard antiviral drugs. Genetic analysis reveals rapid mutation rates in the viral genome. Which property of viruses does this scenario illustrate?

Accepted Answer

Viruses evolve and mutate, leading to new, drug-resistant strains.

Question 5

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

Accepted Answer

Synthesizing viral mRNA

Question 6

A virus is described as having a 20-sided, symmetrical protein shell. What is the term for this type of capsid structure?

Accepted Answer

Icosahedral

Question 7

Which of the following statements about viral genomes is correct?

Accepted Answer

A virus can have either DNA or RNA as its genetic material, but never both.

Question 8

The envelope of an enveloped virus is primarily acquired from which source?

Accepted Answer

The host cell membrane during viral budding

Question 9

Which of the following best describes the Baltimore classification system for viruses?

Accepted Answer

It groups viruses based on their type of nucleic acid and their mechanism of mRNA synthesis.

Question 10

A virus with a helical capsid, RNA genome, and an outer lipid layer with spike proteins is most likely to enter host cells by which mechanism?

Accepted Answer

Fusion of the viral envelope with the host cell membrane

Question 11

Which of the following is a correct example of binomial species naming for viruses, as established by the ICTV?

Accepted Answer

Orthoflavivirus zikaense

Question 12

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

Accepted Answer

Bacteriophage therapy to treat bacterial superbugs

Question 13

Which of the following best describes a virome?

Accepted Answer

The total collection of viruses present in a particular environment, such as the human body or aquatic systems

Question 14

Why is the standardization of virus nomenclature important in scientific and medical communication?

Accepted Answer

It prevents confusion, aids epidemiological tracking, and supports regulatory approval of vaccines and diagnostics.

Question 15

Which of the following is a plausible reason why enveloped viruses are generally less stable outside a host cell compared to non-enveloped viruses?

Accepted Answer

Their lipid envelope is sensitive to desiccation, heat, and detergents.

Question 16

A researcher is studying a virus that infects bacteria and has a complex structure with a head and tail. What is the most likely name for this type of virus?

Accepted Answer

Bacteriophage

Question 17

Which of the following equations best represents the relationship between viral genome type and mRNA synthesis in the Baltimore classification system?

Accepted Answer

$$	ext{Viral Genome} \xrightarrow{	ext{Replication/Transcription}} 	ext{mRNA} \xrightarrow{	ext{Translation}} 	ext{Proteins}$$

Question 18

Which of the following is a correct statement about the structure of a virion?

Accepted Answer

A virion is the fully assembled, infectious form of a virus particle that exists outside of a host cell.

Question 19

Which of the following best explains why viruses are not considered living organisms?

Accepted Answer

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

Question 20

A patient is treated with bacteriophage therapy for a drug-resistant bacterial infection. Which property of bacteriophages makes this therapy effective?

Accepted Answer

Bacteriophages specifically infect and lyse bacterial cells, leaving human cells unharmed.

lec 11:Introduction to Virology: Structure, Classification, and Impact of Viruses

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