Q: Which of the following equations best represents the burst size in a lytic cycle experiment?

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

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. Which type of agent is this most likely to be?

Accepted Answer

A viroid

Question 3

Which of the following best describes the role of the viral envelope?

Accepted Answer

It is composed of a phospholipid bilayer and proteins, some of which are virally encoded glycoproteins that aid in host recognition.

Question 4

During the lytic replication cycle of a bacteriophage, what is the correct order of the stages?

Accepted Answer

Attachment, Entry, Synthesis, Assembly, Release

Question 5

Which of the following is a key difference between the replication of animal viruses and bacteriophages?

Accepted Answer

Animal viruses may enter host cells by membrane fusion or endocytosis, while bacteriophages typically inject their genome.

Question 6

Which of the following equations best represents the burst size in a lytic cycle experiment?

Accepted Answer

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

Question 7

A patient is diagnosed with a disease caused by a prion. Which of the following statements about prions is correct?

Accepted Answer

Prions are proteinaceous infectious agents that cause normal cellular PrP to refold into a disease-causing form.

Question 8

Which of the following best explains why enveloped viruses are generally more fragile than naked viruses?

Accepted Answer

Their envelopes are easily disrupted by environmental factors, leading to loss of infectivity.

Question 9

Which of the following is a real-world example of lysogenic conversion?

Accepted Answer

A bacterium acquires the ability to produce a toxin only after infection by a temperate phage.

Question 10

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

Accepted Answer

The viral genome is released from the capsid after entry into the host cell.

Question 11

Which of the following is a characteristic of viroids but NOT of viruses?

Accepted Answer

They lack a protein coat (capsid).

Question 12

Which of the following is a plausible reason why viruses are not classified as living organisms?

Accepted Answer

They cannot carry out metabolic processes independently.

Question 13

Which of the following best describes the relationship between proto-oncogenes and cancer in the context of viral infection?

Accepted Answer

Viruses can activate proto-oncogenes or carry oncogenes, leading to uncontrolled cell division and cancer.

Question 14

Which of the following is a correct statement about the synthesis of RNA viruses in animal cells?

Accepted Answer

Positive-sense (+) RNA viruses can act directly as mRNA for protein synthesis.

Question 15

A laboratory is attempting to culture a newly discovered virus. Which of the following methods would NOT be effective?

Accepted Answer

Growing the virus in standard nutrient agar without host cells.

Question 16

Which of the following best explains why prion diseases are difficult to control in medical settings?

Accepted Answer

Prions are resistant to standard sterilization procedures and require incineration or autoclaving in concentrated sodium hydroxide for deactivation.

Question 17

Which of the following is a distinguishing feature of retroviruses among RNA viruses?

Accepted Answer

They use reverse transcriptase to synthesize DNA from an RNA template.

Question 18

Which of the following best describes the process of lysogeny in bacteriophages?

Accepted Answer

The phage genome integrates into the host chromosome and replicates along with it without causing immediate lysis.

Question 19

Which of the following is a correct statement about the assembly and release of animal viruses?

Accepted Answer

Most DNA viruses assemble in the nucleus, while most RNA viruses assemble in the cytoplasm.

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

Guida di studio - Domande di pratica

Study guide - Flashcard