Question 1

Which of the following best describes the function of a viral capsid?

Accepted Answer

It is the protein coat that covers and protects the viral genome.

Question 2

A bacteriophage infects a bacterial cell and integrates its DNA into the host genome without killing the cell. What is this process called?

Accepted Answer

Lysogenic cycle

Question 3

Which equation correctly represents the action of reverse transcriptase in retroviruses?

Accepted Answer

$$RNA \rightarrow DNA$$

Question 4

Which of the following is TRUE about viroids?

Accepted Answer

They are short, circular, single-stranded RNA molecules that do not encode proteins.

Question 5

During the lytic cycle of a bacteriophage, which event occurs?

Accepted Answer

The host cell is lysed and new viral particles are released.

Question 6

Which of the following best explains why animal viruses often have envelopes?

Accepted Answer

The envelope is derived from the host cell membrane and helps the virus evade the immune system.

Question 7

A positive sense RNA virus enters a host cell. What is the first step in its replication?

Accepted Answer

Its genome is immediately translated into viral proteins.

Question 8

Which of the following is a distinguishing feature of prions compared to viruses and viroids?

Accepted Answer

Prions are infectious proteins that do not contain nucleic acids.

Question 9

Which process allows a virus to enter a host cell by merging its membrane with the host's membrane?

Accepted Answer

Membrane fusion

Question 10

A temperate phage is capable of which of the following?

Accepted Answer

Replicating through both the lytic and lysogenic cycles

Question 11

Which of the following statements about double-stranded DNA viruses is correct?

Accepted Answer

They enter the nucleus to replicate and often replicate genomes during S phase of the cell cycle.

Question 12

Which of the following is a correct description of a bacteriophage?

Accepted Answer

A virus that infects bacteria and contains complex capsids.

Question 13

What is the role of host cell surface proteins in viral infection?

Accepted Answer

They act as receptors for viral attachment and entry.

Question 14

Which of the following best describes the genome of a negative sense RNA virus?

Accepted Answer

It contains sequences complementary to those coding for viral proteins and must be transcribed by viral RNA polymerase.

Question 15

Which of the following is a correct multi-step sequence for the replication of a retrovirus?

Accepted Answer

Entry into host cell $$\rightarrow$$ reverse transcription $$\rightarrow$$ integration into host genome $$\rightarrow$$ transcription and translation of viral proteins

Question 16

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

Accepted Answer

Integration of viral DNA into the host genome

Question 17

Which of the following best explains why many bacteria have restriction enzymes?

Accepted Answer

To degrade viral DNA and defend against bacteriophage infection

Question 18

Which of the following infectious agents is most likely to disrupt plant growth without encoding any proteins?

Accepted Answer

Viroid

Question 19

A virus with a single-stranded RNA genome that must be transcribed into complementary RNA before translation is classified as:

Accepted Answer

Negative sense RNA virus

Question 20

Which of the following is a correct statement about the role of host cell machinery in viral replication?

Accepted Answer

The host cell provides nucleotides, enzymes, ribosomes, amino acids, and ATP for viral replication.

Viruses and Other Infectious Agents: Structure, Replication, and Classification

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