Question 1

Which of the following best describes the structure of a typical virus particle?

Accepted Answer

A protein capsid containing DNA or RNA, sometimes surrounded by a lipid envelope

Question 2

Which statement correctly explains why viruses are not considered living cells?

Accepted Answer

Viruses lack a cell membrane and cannot perform independent metabolism

Question 3

A virus with a single-stranded RNA genome that must first synthesize a complementary DNA strand before replication is classified as:

Accepted Answer

A retrovirus

Question 4

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

Accepted Answer

It is derived from the host cell membrane and contains viral-encoded proteins

Question 5

During the viral life cycle, which step involves the synthesis of viral proteins using host cell machinery?

Accepted Answer

Translation

Question 6

Which equation best represents the process of reverse transcription in retroviruses?

Accepted Answer

$$RNA \rightarrow DNA \rightarrow mRNA \rightarrow Protein$$

Question 7

A patient is diagnosed with cervical cancer caused by HPV. What is the mechanism by which HPV can lead to cancer?

Accepted Answer

HPV integrates its DNA into the host cell genome, disrupting normal cell cycle regulation

Question 8

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that cause disease by inducing misfolding of normal proteins

Question 9

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

Accepted Answer

Viroids consist solely of a short circular RNA without a protein capsid

Question 10

Which step in the viral life cycle is most directly affected by the presence of coat protein mediated resistance in plants?

Accepted Answer

Assembly

Question 11

A virus infects a cell and uses the host's ribosomes to translate its mRNA. Which type of virus is this most likely to be?

Accepted Answer

A positive-sense single-stranded RNA virus

Question 12

Which of the following best explains why viruses are dependent on host cells for replication?

Accepted Answer

Viruses lack the cellular machinery required for energy production and biosynthesis

Question 13

Which process is represented by the following equation in the context of viral replication? $$DNA \rightarrow mRNA \rightarrow Protein$$

Accepted Answer

Transcription and translation

Question 14

Which of the following viruses is most likely to cause cancer by integrating its genome into host DNA?

Accepted Answer

Oncogenic retrovirus

Question 15

A plant is genetically engineered to express a viral coat protein. What is the expected outcome?

Accepted Answer

The plant will be resistant to infection by that virus due to disruption of viral assembly

Question 16

Which of the following is NOT a step in the general viral life cycle?

Accepted Answer

Binary fission

Question 17

Which enzyme is required for the replication of a negative-sense RNA virus?

Accepted Answer

RNA-dependent RNA polymerase

Question 18

A scientist observes that a virus cannot assemble unless a critical concentration of capsid protein is reached. This phenomenon is best explained by:

Accepted Answer

Dynamic equilibrium of assembly and disassembly

Question 19

Which of the following is a plausible route for the transmission of viroids?

Accepted Answer

By insects or plantation workers spreading RNA to plants

Question 20

Which of the following best describes the difference between a virus and a prion?

Accepted Answer

A virus contains nucleic acid, while a prion is a misfolded protein without nucleic acid

Comprehensive Study Notes on Viral Structure, Life Cycle, and Pathogenesis

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