Question 1

Which of the following statements best distinguishes viruses from bacteria?

Accepted Answer

Viruses are obligate intracellular parasites, while bacteria can often reproduce independently.

Question 2

A scientist isolates a pathogen that contains single-stranded RNA, a protein coat, and no ribosomes. Which of the following best describes this pathogen?

Accepted Answer

A virus

Question 3

Which of the following is NOT a possible form of viral nucleic acid?

Accepted Answer

Both single-stranded DNA and single-stranded RNA in the same virion

Question 4

The host range of a virus is primarily determined by:

Accepted Answer

Specific attachment sites on the host cell and compatible cellular factors

Question 5

Which of the following best describes the structure of an enveloped virus?

Accepted Answer

A protein capsid surrounded by a lipid bilayer derived from the host cell membrane

Question 6

Which of the following is a correct statement about prions?

Accepted Answer

Prions are infectious agents composed only of protein.

Question 7

A virus that infects bacteria is called a:

Accepted Answer

Bacteriophage

Question 8

Which of the following best explains why viruses are considered acellular?

Accepted Answer

They lack a plasma membrane and do not undergo cell division.

Question 9

Which of the following steps is unique to the replication of enveloped viruses compared to non-enveloped viruses?

Accepted Answer

Penetration by membrane fusion

Question 10

A patient is diagnosed with Creutzfeldt-Jakob disease. Which of the following statements about the causative agent is correct?

Accepted Answer

It is a prion, consisting only of misfolded protein.

Question 11

Which of the following best describes the process by which an enveloped virus acquires its envelope?

Accepted Answer

By budding from the host cell membrane, incorporating host lipids and viral proteins

Question 12

Which of the following is a property shared by all viruses?

Accepted Answer

They require host cell ribosomes for protein synthesis.

Question 13

A virus is described as having an icosahedral capsid and an envelope. Which of the following viruses fits this description?

Accepted Answer

SARS-CoV-2

Question 14

Which of the following best explains why viruses can rapidly increase in number within a host cell?

Accepted Answer

Viral components are synthesized independently and then assembled into many particles.

Question 15

Which of the following is NOT a characteristic of prion diseases?

Accepted Answer

They are treated effectively with antibiotics.

Question 16

Which of the following scenarios best illustrates the concept of host range in viruses?

Accepted Answer

A bacteriophage infects only E. coli due to specific receptor binding.

Question 17

Which of the following is a correct comparison between the replication of viruses and bacteria?

Accepted Answer

Viruses assemble from pre-formed components, while bacteria replicate by binary fission.

Question 18

Which of the following is a plausible reason why antibiotics are ineffective against viruses?

Accepted Answer

Viruses lack the metabolic pathways targeted by antibiotics.

Question 19

Which of the following best describes the genome of a typical eukaryotic host cell compared to a virus?

Accepted Answer

Eukaryotic cells have linear DNA chromosomes; viruses may have linear or circular DNA or RNA.

Question 20

Which of the following is a real-world example of a prion disease affecting animals?

Accepted Answer

Bovine spongiform encephalopathy (BSE) in cattle

Viruses and Prions: Structure, Classification, and Replication

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