Microbiology Week 7: Virology and Viral Pathogenesis 2026 |WGU
1. What is the primary protein shell that surrounds the nucleic acid of a virus?
A. Envelope
B. Capsomere
C. Spike
D. Capsid
Answer: D
Rationale: The capsid is the protein shell that encloses the viral genome. Capsomeres are
the individual protein subunits that make up the capsid.
2. Which enzyme is characteristic of retroviruses like HIV to convert their RNA
genome into DNA?
A. RNA polymerase
B. DNA ligase
C. Reverse transcriptase
D. Helicase
Answer: C
Rationale: Reverse transcriptase allows retroviruses to synthesize complementary DNA
(cDNA) from an RNA template.
,3. In which stage of the viral replication cycle does the virus attach to specific
receptors on the host cell?
A. Penetration
B. Adsorption
C. Uncoating
D. Assembly
Answer: B
Rationale: Adsorption, or attachment, is the first step where viral surface proteins bind to
specific host cell receptors.
4. What is a ‘prophage’?
A. A virus that infects bacteria
B. Phage DNA integrated into the host bacterial chromosome
C. The protein coat of a bacteriophage
D. A virus that has just been released from a cell
Answer: B
Rationale: In the lysogenic cycle, the viral DNA integrates into the bacterial chromosome
and is then referred to as a prophage.
5. Which of the following describes a virus that lacks an envelope?
A. Complex virus
B. Naked virus
C. Enveloped virus
D. Viroid
Answer: B
Rationale: Viruses consisting only of a nucleocapsid without a surrounding lipid
membrane are called naked viruses.
, 6. Prions are infectious agents composed entirely of:
A. RNA
B. DNA
C. Protein
D. Lipids
Answer: C
Rationale: Prions are misfolded infectious proteins that contain no nucleic acids.
7. What term describes the morphological changes in host cells caused by viral
invasion?
A. Lytic effect
B. Transformation
C. Cytopathic effect (CPE)
D. Apoptosis
Answer: C
Rationale: Cytopathic effects are visible signs of viral infection in host cells, such as cell
rounding, fusion, or inclusion bodies.
8. Which viral life cycle results in the immediate rupture and death of the host
cell?
A. Lytic cycle
B. Lysogenic cycle
C. Latent cycle
D. Persistent cycle
Answer: A
Rationale: The lytic cycle culminates in the lysis of the host cell to release new virions.
1. What is the primary protein shell that surrounds the nucleic acid of a virus?
A. Envelope
B. Capsomere
C. Spike
D. Capsid
Answer: D
Rationale: The capsid is the protein shell that encloses the viral genome. Capsomeres are
the individual protein subunits that make up the capsid.
2. Which enzyme is characteristic of retroviruses like HIV to convert their RNA
genome into DNA?
A. RNA polymerase
B. DNA ligase
C. Reverse transcriptase
D. Helicase
Answer: C
Rationale: Reverse transcriptase allows retroviruses to synthesize complementary DNA
(cDNA) from an RNA template.
,3. In which stage of the viral replication cycle does the virus attach to specific
receptors on the host cell?
A. Penetration
B. Adsorption
C. Uncoating
D. Assembly
Answer: B
Rationale: Adsorption, or attachment, is the first step where viral surface proteins bind to
specific host cell receptors.
4. What is a ‘prophage’?
A. A virus that infects bacteria
B. Phage DNA integrated into the host bacterial chromosome
C. The protein coat of a bacteriophage
D. A virus that has just been released from a cell
Answer: B
Rationale: In the lysogenic cycle, the viral DNA integrates into the bacterial chromosome
and is then referred to as a prophage.
5. Which of the following describes a virus that lacks an envelope?
A. Complex virus
B. Naked virus
C. Enveloped virus
D. Viroid
Answer: B
Rationale: Viruses consisting only of a nucleocapsid without a surrounding lipid
membrane are called naked viruses.
, 6. Prions are infectious agents composed entirely of:
A. RNA
B. DNA
C. Protein
D. Lipids
Answer: C
Rationale: Prions are misfolded infectious proteins that contain no nucleic acids.
7. What term describes the morphological changes in host cells caused by viral
invasion?
A. Lytic effect
B. Transformation
C. Cytopathic effect (CPE)
D. Apoptosis
Answer: C
Rationale: Cytopathic effects are visible signs of viral infection in host cells, such as cell
rounding, fusion, or inclusion bodies.
8. Which viral life cycle results in the immediate rupture and death of the host
cell?
A. Lytic cycle
B. Lysogenic cycle
C. Latent cycle
D. Persistent cycle
Answer: A
Rationale: The lytic cycle culminates in the lysis of the host cell to release new virions.
