Q: Which of the following equations correctly represents the process by which a retrovirus converts its RNA genome into DNA?

$$RNA \xrightarrow{\text{reverse transcriptase}} DNA$$

Q: Which of the following equations best represents the synthesis of mRNA from a double-stranded DNA viral genome?

$$dsDNA \xrightarrow{\text{host RNA polymerase}} mRNA$$

Question 1

Which of the following best describes the main criterion used in the Baltimore classification system for viruses?

Accepted Answer

The form of the viral genome and its method of mRNA synthesis

Question 2

A virus with a single-stranded, negative-sense RNA genome must encode which enzyme for replication in its host cell?

Accepted Answer

RNA-dependent RNA polymerase

Question 3

Which of the following steps is unique to the replication cycle of retroviruses (Baltimore Group VI)?

Accepted Answer

Reverse transcription of RNA to DNA

Question 4

Which mechanism is NOT a way that oncogenic viruses can transform a host cell?

Accepted Answer

Direct lysis of the host cell

Question 5

Plant viruses typically enter host cells by which of the following mechanisms?

Accepted Answer

Mechanical transmission through damaged tissues

Question 6

Which of the following equations correctly represents the process by which a retrovirus converts its RNA genome into DNA?

Accepted Answer

$$RNA \xrightarrow{	ext{reverse transcriptase}} DNA$$

Question 7

Which of the following best explains why all animal viruses use host ribosomes for protein synthesis?

Accepted Answer

Host ribosomes are required for translation of viral mRNA

Question 8

A patient is diagnosed with a viral infection caused by a Group IV virus. Which of the following best describes the genome of this virus?

Accepted Answer

Single-stranded, positive-sense RNA

Question 9

Which of the following is a real-world example of a virus that can cause cancer by integrating its genome into the host DNA?

Accepted Answer

Epstein-Barr virus

Question 10

Which of the following statements about viral envelopes is correct?

Accepted Answer

Enveloped viruses acquire their envelope by budding through a membrane

Question 11

Which of the following best describes the role of RNA interference (RNAi) in host defense against viruses?

Accepted Answer

It blocks translation of viral mRNA by degrading it

Question 12

A virus is found to persist in wild animal populations and occasionally infects humans, causing outbreaks. Which of the following factors most likely contributes to its persistence?

Accepted Answer

A broad host range

Question 13

Which of the following is a correct sequence of events for the entry of influenza virus into a host cell?

Accepted Answer

Attachment to sialic acid receptor → Endocytosis → Acidification of endosome → Fusion of viral and endosomal membranes

Question 14

Which of the following equations best represents the synthesis of mRNA from a double-stranded DNA viral genome?

Accepted Answer

$$dsDNA \xrightarrow{	ext{host RNA polymerase}} mRNA$$

Question 15

Which of the following is a plausible reason why viruses are considered important for maintaining ecosystem balance?

Accepted Answer

They limit host population density and promote host diversity

Question 16

A new viral pathogen emerges in humans after people consume wildlife. Which of the following best explains this phenomenon?

Accepted Answer

The virus crossed the species barrier due to close contact with wildlife

Question 17

Which of the following best describes the process by which an enveloped virus is released from a host cell?

Accepted Answer

Budding through a membrane, acquiring a lipid envelope

Question 18

Which of the following is a correct description of the function of viral hemagglutinin in influenza infection?

Accepted Answer

It attaches to sialic acid receptors on host cells

Question 19

Which of the following is a plausible outcome if a virus integrates its genome into the host cell's DNA?

Accepted Answer

The host cell may become cancerous

Question 20

Which of the following best explains why plant viruses often require an animal vector for transmission?

Accepted Answer

Plant viruses cannot bind to specific membrane receptors

Molecular Aspects of Viruses: Baltimore Classification, Replication, and Viral Ecology

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