Question 1

Which of the following statements best describes the genetic material of viruses?

Accepted Answer

Viruses may have DNA or RNA, which can be single-stranded or double-stranded, linear or circular.

Question 2

A scientist discovers a new infectious agent that consists solely of a small, circular piece of single-stranded RNA and lacks a protein coat. Which type of agent is this most likely to be?

Accepted Answer

A viroid

Question 3

During the lytic replication cycle of a bacteriophage, which stage immediately follows the synthesis of viral components?

Accepted Answer

Assembly

Question 4

Which of the following best explains why most animal DNA viruses replicate their genomes in the nucleus, while most RNA viruses replicate in the cytoplasm?

Accepted Answer

DNA viruses require host DNA polymerases found in the nucleus, while RNA viruses use their own enzymes in the cytoplasm.

Question 5

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

Accepted Answer

Prions are infectious proteins that cause normal proteins to misfold.

Question 6

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

Accepted Answer

The lysogenic cycle allows the host cell to survive and divide with the prophage, while the lytic cycle results in host cell lysis.

Question 7

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

Accepted Answer

They serve as recognition sites for host cell attachment.

Question 8

A virus with a single-stranded, negative-sense RNA genome must first synthesize which of the following to produce viral proteins?

Accepted Answer

A complementary positive-sense RNA strand

Question 9

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

Accepted Answer

A bacterium produces a toxin only after infection by a temperate phage carrying the toxin gene.

Question 10

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

Accepted Answer

Their phospholipid envelopes are easily disrupted by detergents and drying.

Question 11

A retrovirus differs from other RNA viruses in that it:

Accepted Answer

Uses reverse transcriptase to synthesize DNA from its RNA genome.

Question 12

Which of the following is NOT a step in the lytic replication cycle of a bacteriophage?

Accepted Answer

Lysogeny

Question 13

A virus infects a host cell and is released by budding. What is the most likely consequence for the host cell?

Accepted Answer

Persistent infection with continued survival of the host cell

Question 14

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 15

Which of the following equations best represents the burst size in a lytic bacteriophage infection, where $$N_{virions} is $$the number of virions released and $$N_{cells} is $$the number of infected cells?

Accepted Answer

$$Burst\ size = \frac{N_{virions}}{N_{cells}}$$

Question 16

Which of the following is a characteristic unique to viroids compared to viruses?

Accepted Answer

They lack a protein capsid and do not code for proteins.

Question 17

A patient develops a malignant tumor after infection with a certain virus. Which of the following mechanisms is LEAST likely to explain the virus-induced cancer?

Accepted Answer

The virus directly lyses all host cells, preventing cell division.

Question 18

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

Accepted Answer

Prions are resistant to heat, radiation, and most chemicals used for sterilization.

Question 19

Which of the following is a correct statement about the host range of viruses?

Accepted Answer

Most viruses are highly specific, infecting only particular cell types due to protein-protein interactions.

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

Guida di studio - Domande di pratica

Study guide - Flashcard