Q: Which of the following equations best represents the burst size in a lytic bacteriophage infection?

$$\text{Burst size} = \frac{\text{Number of virions released}}{\text{Number of infected cells}}$$

Question 1

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

Accepted Answer

They lack a cytoplasmic membrane, cytosol, and organelles.

Question 2

A scientist discovers a new infectious agent that consists of a small, circular piece of single-stranded RNA without a protein coat, causing disease in plants. What is this agent most likely to be?

Accepted Answer

A viroid

Question 3

Which of the following best describes the process of lysogenic conversion in bacteria?

Accepted Answer

A bacteriophage integrates its genome into the host chromosome, potentially altering the host's phenotype.

Question 4

Which of the following is a correct statement about the replication of animal viruses with a double-stranded DNA genome?

Accepted Answer

The viral genome is replicated in the nucleus, while viral proteins are synthesized in the cytoplasm.

Question 5

A patient presents with rapidly progressive dementia and spongiform changes in brain tissue. Which infectious agent is most likely responsible, and what is its main structural feature?

Accepted Answer

A prion; composed of misfolded proteins with β-sheets

Question 6

Which of the following best explains why enveloped viruses are generally more sensitive to environmental conditions than naked viruses?

Accepted Answer

Their phospholipid envelope is easily disrupted by detergents and desiccation.

Question 7

A virus with a single-stranded, negative-sense RNA genome must first perform which step before it can synthesize viral proteins?

Accepted Answer

Synthesize a complementary positive-sense RNA strand to serve as mRNA

Question 8

Which of the following is NOT a typical method for culturing viruses in the laboratory?

Accepted Answer

Growing viruses in nutrient agar plates without host cells

Question 9

A virus is classified as a generalist. What does this mean regarding its host range?

Accepted Answer

It can infect many kinds of cells or different hosts.

Question 10

Which of the following best describes the role of proto-oncogenes in the development of cancer by viruses?

Accepted Answer

Viruses can activate proto-oncogenes or introduce oncogenes, leading to uncontrolled cell division.

Question 11

Which of the following equations best represents the burst size in a lytic bacteriophage infection?

Accepted Answer

$$	ext{Burst size} = \frac{	ext{Number of virions released}}{	ext{Number of infected cells}}$$

Question 12

Which of the following is a unique feature of prions compared to all other infectious agents?

Accepted Answer

They lack nucleic acids and are composed solely of protein.

Question 13

A researcher is studying a virus that enters animal cells by membrane fusion. Which of the following must be true about this virus?

Accepted Answer

It is an enveloped virus.

Question 14

Which of the following best explains why normal sterilization procedures are ineffective against prions?

Accepted Answer

Prions are resistant to heat and chemicals that denature proteins and nucleic acids.

Question 15

Which of the following is a correct statement about the genetic material of viruses?

Accepted Answer

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

Question 16

A patient is diagnosed with cervical cancer linked to a viral infection. Which virus family is most likely responsible?

Accepted Answer

Papillomaviridae

Question 17

Which of the following best describes the process of uncoating in animal virus replication?

Accepted Answer

The removal of the capsid to release the viral genome inside the host cell

Question 18

Which of the following is a real-world example of a disease caused by a viroid?

Accepted Answer

Potato spindle tuber disease

Question 19

Which of the following is a key difference between the lytic and lysogenic cycles of bacteriophage replication?

Accepted Answer

The lysogenic cycle involves integration of the phage genome into the host chromosome, while the lytic cycle does not.

Question 20

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

Accepted Answer

They require host cell machinery to carry out replication and metabolism.

Characterizing and Classifying Viruses, Viroids, and Prions: Study Notes

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