BIOL 271 Microbiology w/ Lab Module 5 Exam Review
Advanced/Hard Difficulty | College/University Level | 150
Questions
SECTION 1: VIROLOGY – Structure, Classification, and Replication
🟢 1. A novel virus is isolated from a patient with hemorrhagic fever. Electron microscopy
reveals a helical nucleocapsid, an envelope with prominent glycoprotein spikes, and a
negative-sense single-stranded RNA genome. Which of the following viral families does this
virus MOST likely belong to?
A) Picornaviridae
B) Filoviridae
C) Adenoviridae
D) Reoviridae
✅ Correct Answer: B – Filoviridae (e.g., Ebola virus) are enveloped, helical, negative-sense
ssRNA viruses. Picornaviridae are non-enveloped, positive-sense ssRNA; Adenoviridae are
non-enveloped dsDNA; Reoviridae are non-enveloped dsRNA.
🟢 2. During the lytic cycle of a bacteriophage, the viral genome is replicated and phage
proteins are synthesized, leading to host cell lysis. Which of the following events occurs FIRST
during the lytic cycle of T-even bacteriophages?
A) Integration of viral DNA into the host chromosome
B) Injection of viral DNA into the host cell
C) Assembly of new phage particles
D) Release of progeny phages via budding
✅ Correct Answer: B – Injection of viral DNA into the host cell is the first step following
attachment. Integration occurs in the lysogenic cycle, assembly occurs mid-cycle, and
budding is characteristic of enveloped animal viruses, not T-even phages.
🟢 3. A 45-year-old immunocompromised patient presents with progressive multifocal
leukoencephalopathy (PML). Which virus is the MOST common cause of this demyelinating
disease?
A) JC virus
B) BK virus
C) Epstein-Barr virus
D) Cytomegalovirus
✅ Correct Answer: A – JC virus, a polyomavirus, causes PML in immunocompromised
individuals. BK virus causes nephropathy; EBV causes mononucleosis and lymphomas; CMV
causes retinitis and pneumonitis.
🟢 4. Which of the following correctly describes the difference between a virus and a virion?
A) A virus is the infectious extracellular form; a virion is the intracellular replicative form
B) A virion is the complete infectious viral particle; a virus refers to the genetic material only
C) A virion is the complete infectious particle; a virus is a general term for the organism
, D) There is no difference; the terms are interchangeable
✅ Correct Answer: C – A virion is the complete, infectious viral particle consisting of nucleic
acid surrounded by a protein capsid (and possibly an envelope). "Virus" is the general term
for the infectious agent.
🟢 5. Which of the following viral enzymes is ESSENTIAL for the replication of retroviruses such
as HIV?
A) RNA-dependent RNA polymerase
B) Reverse transcriptase
C) DNA-dependent DNA polymerase
D) Neuraminidase
✅ Correct Answer: B – Reverse transcriptase converts the viral RNA genome into DNA,
which is then integrated into the host genome. RNA-dependent RNA polymerase is used by
RNA viruses; neuraminidase is an influenza enzyme.
🟢 6. A researcher is studying a virus that requires the host cell's RNA polymerase II to
transcribe its genome. Based on this requirement, the virus MOST likely has which type of
genome?
A) Positive-sense single-stranded RNA
B) Negative-sense single-stranded RNA
C) Double-stranded DNA
D) Single-stranded DNA
✅ Correct Answer: C – Double-stranded DNA viruses typically use host RNA polymerase II
for transcription. Positive-sense ssRNA can be directly translated; negative-sense ssRNA
requires a viral RNA-dependent RNA polymerase.
🟢 7. A patient presents with a respiratory infection. A sputum sample is cultured and reveals
no bacterial growth, but a cytopathic effect is observed in cell culture. Electron microscopy
shows an enveloped, segmented, negative-sense RNA virus. Which virus is MOST likely
responsible?
A) Respiratory syncytial virus (RSV)
B) Influenza virus
C) Rhinovirus
D) Adenovirus
✅ Correct Answer: B – Influenza virus is an enveloped, segmented, negative-sense RNA
virus. RSV is non-segmented; Rhinovirus is non-enveloped positive-sense RNA; Adenovirus is
non-enveloped dsDNA.
🟢 8. The phenomenon of antigenic shift in influenza viruses is primarily caused by:
A) Accumulation of point mutations in the hemagglutinin gene
B) Reassortment of segmented RNA genomes between different influenza strains
C) Deletions in the neuraminidase gene
D) Host immune selection pressure
✅ Correct Answer: B – Antigenic shift results from reassortment of segmented RNA
genomes when two different influenza strains infect the same host cell. Antigenic drift is
caused by point mutations (A).
,🟢 9. Which of the following viral replication strategies involves the integration of viral DNA
into the host genome as a provirus, followed by a period of latency?
A) Lytic cycle of bacteriophage T4
B) Lysogenic cycle of bacteriophage lambda
C) Replication of poliovirus
D) Replication of rhinovirus
✅ Correct Answer: B – The lysogenic cycle involves integration of phage DNA into the host
chromosome as a prophage, remaining latent. The lytic cycle (A) results in host cell lysis;
poliovirus and rhinovirus are RNA viruses that do not integrate.
🟢 10. A 28-year-old pregnant woman is concerned about a recent exposure to a virus that
causes congenital malformations. Which of the following viruses is a well-established TORCH
pathogen known for causing congenital infections?
A) Human papillomavirus (HPV)
B) Cytomegalovirus (CMV)
C) Human immunodeficiency virus (HIV)
D) Hepatitis B virus (HBV)
✅ Correct Answer: B – CMV is a classic TORCH pathogen (Toxoplasmosis, Other, Rubella,
CMV, HSV). HPV causes warts and cancers; HIV and HBV can be transmitted perinatally but
are not traditionally classified as TORCH pathogens.
🟢 11. Which of the following correctly describes the Baltimore classification of viruses?
A) Classification based on the type of host they infect
B) Classification based on the nature of the viral genome and its replication strategy
C) Classification based on the shape of the capsid
D) Classification based on the presence or absence of an envelope
✅ Correct Answer: B – The Baltimore classification groups viruses into seven classes based
on their genome type (DNA/RNA, ss/ds) and replication strategy. It does not consider host,
capsid shape, or envelope.
🟢 12. A virus is found to have an icosahedral capsid, a non-enveloped structure, and a
positive-sense single-stranded RNA genome. It is transmitted via the fecal-oral route and
causes poliomyelitis. This virus belongs to which family?
A) Picornaviridae
B) Caliciviridae
C) Flaviviridae
D) Togaviridae
✅ Correct Answer: A – Picornaviridae (poliovirus, rhinovirus) are non-enveloped,
icosahedral, positive-sense ssRNA viruses transmitted fecal-orally. Caliciviridae cause
gastroenteritis; Flaviviridae and Togaviridae are enveloped.
🟢 13. The measles virus (rubeola) is an enveloped, negative-sense, single-stranded RNA virus.
Its attachment to host cells is mediated by which of the following glycoproteins?
A) Hemagglutinin (H) and Fusion (F) proteins
B) Hemagglutinin (HA) and Neuraminidase (NA)
C) gp120 and gp41
, D) E1 and E2
✅ Correct Answer: A – Measles virus uses H and F proteins for attachment and fusion. HA
and NA are influenza proteins; gp120/gp41 are HIV proteins; E1/E2 are alphavirus proteins.
🟢 14. Which of the following statements about viral latency is CORRECT?
A) During latency, the virus is actively replicating and producing progeny virions
B) Latency is characterized by the presence of viral genome without production of infectious
particles
C) Latency only occurs in DNA viruses
D) Latent viruses are always cleared by the host immune system
✅ Correct Answer: B – Latency is a state where the viral genome persists in the host cell
without producing infectious progeny. RNA viruses (e.g., HIV) can also establish latency.
Latent viruses are not always cleared.
🟢 15. A 55-year-old patient with a history of chickenpox in childhood now presents with a
painful, vesicular rash along a dermatomal distribution on the right thorax. Which virus is
MOST likely responsible?
A) Herpes simplex virus type 1 (HSV-1)
B) Herpes simplex virus type 2 (HSV-2)
C) Varicella-zoster virus (VZV)
D) Epstein-Barr virus (EBV)
✅ Correct Answer: C – VZV causes chickenpox (primary) and shingles (reactivation)
presenting as a painful vesicular rash along a dermatome. HSV-1 causes oral herpes; HSV-2
causes genital herpes; EBV causes mononucleosis.
SECTION 2: MYCOLOGY – Fungal Structure, Reproduction, and
Pathogenesis
🟢 16. A 32-year-old immunocompetent patient presents with a chronic, non-healing ulcer on
the foot after stepping on a thorn while gardening in the southwestern United States. The
lesion is characterized by a raised border and purulent drainage. A fungal culture reveals a
dematiaceous (darkly pigmented) mold. Which of the following is the MOST likely causative
agent?
A) Sporothrix schenckii
B) Coccidioides immitis
C) Fonsecaea pedrosoi
D) Candida albicans
✅ Correct Answer: C – Fonsecaea pedrosoi is a dematiaceous fungus causing
chromoblastomycosis, often following traumatic inoculation. Sporothrix causes sporotrichosis
(rose gardener's disease); Coccidioides causes valley fever; Candida causes candidiasis.
🟢 17. A 65-year-old diabetic patient presents with a black, necrotic eschar on the palate and
facial swelling. A biopsy reveals broad, non-septate hyphae with right-angle branching. Which
of the following is the MOST likely diagnosis?
A) Aspergillosis
B) Mucormycosis
Advanced/Hard Difficulty | College/University Level | 150
Questions
SECTION 1: VIROLOGY – Structure, Classification, and Replication
🟢 1. A novel virus is isolated from a patient with hemorrhagic fever. Electron microscopy
reveals a helical nucleocapsid, an envelope with prominent glycoprotein spikes, and a
negative-sense single-stranded RNA genome. Which of the following viral families does this
virus MOST likely belong to?
A) Picornaviridae
B) Filoviridae
C) Adenoviridae
D) Reoviridae
✅ Correct Answer: B – Filoviridae (e.g., Ebola virus) are enveloped, helical, negative-sense
ssRNA viruses. Picornaviridae are non-enveloped, positive-sense ssRNA; Adenoviridae are
non-enveloped dsDNA; Reoviridae are non-enveloped dsRNA.
🟢 2. During the lytic cycle of a bacteriophage, the viral genome is replicated and phage
proteins are synthesized, leading to host cell lysis. Which of the following events occurs FIRST
during the lytic cycle of T-even bacteriophages?
A) Integration of viral DNA into the host chromosome
B) Injection of viral DNA into the host cell
C) Assembly of new phage particles
D) Release of progeny phages via budding
✅ Correct Answer: B – Injection of viral DNA into the host cell is the first step following
attachment. Integration occurs in the lysogenic cycle, assembly occurs mid-cycle, and
budding is characteristic of enveloped animal viruses, not T-even phages.
🟢 3. A 45-year-old immunocompromised patient presents with progressive multifocal
leukoencephalopathy (PML). Which virus is the MOST common cause of this demyelinating
disease?
A) JC virus
B) BK virus
C) Epstein-Barr virus
D) Cytomegalovirus
✅ Correct Answer: A – JC virus, a polyomavirus, causes PML in immunocompromised
individuals. BK virus causes nephropathy; EBV causes mononucleosis and lymphomas; CMV
causes retinitis and pneumonitis.
🟢 4. Which of the following correctly describes the difference between a virus and a virion?
A) A virus is the infectious extracellular form; a virion is the intracellular replicative form
B) A virion is the complete infectious viral particle; a virus refers to the genetic material only
C) A virion is the complete infectious particle; a virus is a general term for the organism
, D) There is no difference; the terms are interchangeable
✅ Correct Answer: C – A virion is the complete, infectious viral particle consisting of nucleic
acid surrounded by a protein capsid (and possibly an envelope). "Virus" is the general term
for the infectious agent.
🟢 5. Which of the following viral enzymes is ESSENTIAL for the replication of retroviruses such
as HIV?
A) RNA-dependent RNA polymerase
B) Reverse transcriptase
C) DNA-dependent DNA polymerase
D) Neuraminidase
✅ Correct Answer: B – Reverse transcriptase converts the viral RNA genome into DNA,
which is then integrated into the host genome. RNA-dependent RNA polymerase is used by
RNA viruses; neuraminidase is an influenza enzyme.
🟢 6. A researcher is studying a virus that requires the host cell's RNA polymerase II to
transcribe its genome. Based on this requirement, the virus MOST likely has which type of
genome?
A) Positive-sense single-stranded RNA
B) Negative-sense single-stranded RNA
C) Double-stranded DNA
D) Single-stranded DNA
✅ Correct Answer: C – Double-stranded DNA viruses typically use host RNA polymerase II
for transcription. Positive-sense ssRNA can be directly translated; negative-sense ssRNA
requires a viral RNA-dependent RNA polymerase.
🟢 7. A patient presents with a respiratory infection. A sputum sample is cultured and reveals
no bacterial growth, but a cytopathic effect is observed in cell culture. Electron microscopy
shows an enveloped, segmented, negative-sense RNA virus. Which virus is MOST likely
responsible?
A) Respiratory syncytial virus (RSV)
B) Influenza virus
C) Rhinovirus
D) Adenovirus
✅ Correct Answer: B – Influenza virus is an enveloped, segmented, negative-sense RNA
virus. RSV is non-segmented; Rhinovirus is non-enveloped positive-sense RNA; Adenovirus is
non-enveloped dsDNA.
🟢 8. The phenomenon of antigenic shift in influenza viruses is primarily caused by:
A) Accumulation of point mutations in the hemagglutinin gene
B) Reassortment of segmented RNA genomes between different influenza strains
C) Deletions in the neuraminidase gene
D) Host immune selection pressure
✅ Correct Answer: B – Antigenic shift results from reassortment of segmented RNA
genomes when two different influenza strains infect the same host cell. Antigenic drift is
caused by point mutations (A).
,🟢 9. Which of the following viral replication strategies involves the integration of viral DNA
into the host genome as a provirus, followed by a period of latency?
A) Lytic cycle of bacteriophage T4
B) Lysogenic cycle of bacteriophage lambda
C) Replication of poliovirus
D) Replication of rhinovirus
✅ Correct Answer: B – The lysogenic cycle involves integration of phage DNA into the host
chromosome as a prophage, remaining latent. The lytic cycle (A) results in host cell lysis;
poliovirus and rhinovirus are RNA viruses that do not integrate.
🟢 10. A 28-year-old pregnant woman is concerned about a recent exposure to a virus that
causes congenital malformations. Which of the following viruses is a well-established TORCH
pathogen known for causing congenital infections?
A) Human papillomavirus (HPV)
B) Cytomegalovirus (CMV)
C) Human immunodeficiency virus (HIV)
D) Hepatitis B virus (HBV)
✅ Correct Answer: B – CMV is a classic TORCH pathogen (Toxoplasmosis, Other, Rubella,
CMV, HSV). HPV causes warts and cancers; HIV and HBV can be transmitted perinatally but
are not traditionally classified as TORCH pathogens.
🟢 11. Which of the following correctly describes the Baltimore classification of viruses?
A) Classification based on the type of host they infect
B) Classification based on the nature of the viral genome and its replication strategy
C) Classification based on the shape of the capsid
D) Classification based on the presence or absence of an envelope
✅ Correct Answer: B – The Baltimore classification groups viruses into seven classes based
on their genome type (DNA/RNA, ss/ds) and replication strategy. It does not consider host,
capsid shape, or envelope.
🟢 12. A virus is found to have an icosahedral capsid, a non-enveloped structure, and a
positive-sense single-stranded RNA genome. It is transmitted via the fecal-oral route and
causes poliomyelitis. This virus belongs to which family?
A) Picornaviridae
B) Caliciviridae
C) Flaviviridae
D) Togaviridae
✅ Correct Answer: A – Picornaviridae (poliovirus, rhinovirus) are non-enveloped,
icosahedral, positive-sense ssRNA viruses transmitted fecal-orally. Caliciviridae cause
gastroenteritis; Flaviviridae and Togaviridae are enveloped.
🟢 13. The measles virus (rubeola) is an enveloped, negative-sense, single-stranded RNA virus.
Its attachment to host cells is mediated by which of the following glycoproteins?
A) Hemagglutinin (H) and Fusion (F) proteins
B) Hemagglutinin (HA) and Neuraminidase (NA)
C) gp120 and gp41
, D) E1 and E2
✅ Correct Answer: A – Measles virus uses H and F proteins for attachment and fusion. HA
and NA are influenza proteins; gp120/gp41 are HIV proteins; E1/E2 are alphavirus proteins.
🟢 14. Which of the following statements about viral latency is CORRECT?
A) During latency, the virus is actively replicating and producing progeny virions
B) Latency is characterized by the presence of viral genome without production of infectious
particles
C) Latency only occurs in DNA viruses
D) Latent viruses are always cleared by the host immune system
✅ Correct Answer: B – Latency is a state where the viral genome persists in the host cell
without producing infectious progeny. RNA viruses (e.g., HIV) can also establish latency.
Latent viruses are not always cleared.
🟢 15. A 55-year-old patient with a history of chickenpox in childhood now presents with a
painful, vesicular rash along a dermatomal distribution on the right thorax. Which virus is
MOST likely responsible?
A) Herpes simplex virus type 1 (HSV-1)
B) Herpes simplex virus type 2 (HSV-2)
C) Varicella-zoster virus (VZV)
D) Epstein-Barr virus (EBV)
✅ Correct Answer: C – VZV causes chickenpox (primary) and shingles (reactivation)
presenting as a painful vesicular rash along a dermatome. HSV-1 causes oral herpes; HSV-2
causes genital herpes; EBV causes mononucleosis.
SECTION 2: MYCOLOGY – Fungal Structure, Reproduction, and
Pathogenesis
🟢 16. A 32-year-old immunocompetent patient presents with a chronic, non-healing ulcer on
the foot after stepping on a thorn while gardening in the southwestern United States. The
lesion is characterized by a raised border and purulent drainage. A fungal culture reveals a
dematiaceous (darkly pigmented) mold. Which of the following is the MOST likely causative
agent?
A) Sporothrix schenckii
B) Coccidioides immitis
C) Fonsecaea pedrosoi
D) Candida albicans
✅ Correct Answer: C – Fonsecaea pedrosoi is a dematiaceous fungus causing
chromoblastomycosis, often following traumatic inoculation. Sporothrix causes sporotrichosis
(rose gardener's disease); Coccidioides causes valley fever; Candida causes candidiasis.
🟢 17. A 65-year-old diabetic patient presents with a black, necrotic eschar on the palate and
facial swelling. A biopsy reveals broad, non-septate hyphae with right-angle branching. Which
of the following is the MOST likely diagnosis?
A) Aspergillosis
B) Mucormycosis
