BIOL 271 Microbiology w/ Lab Module 5 Exam Review V2.0
Advanced/Hard Difficulty | College/University Level | 150 Questions
Comprehensive Coverage: Virology, Mycology, Parasitology, Epidemiology, Diagnostics, Immunology, Antimicrobial
Therapy, and Emerging Diseases
SECTION 1: VIROLOGY – Advanced Molecular Mechanisms and Pathogenesis
🟢 1. A novel virus is isolated from a patient with hemorrhagic fever in South America. Electron microscopy reveals a spherical, enveloped virion with a
helical nucleocapsid and a negative-sense single-stranded RNA genome that is non-segmented. The virus encodes a unique "capping" enzyme that steals
5' caps from host mRNAs (cap-snatching). Which viral family does this virus MOST likely belong to?
A) Arenaviridae
B) Bunyaviridae
C) Filoviridae
D) Orthomyxoviridae
✅ Correct Answer: A – Arenaviruses (e.g., Lassa virus, Junin virus) are enveloped, helical, negative-sense ssRNA viruses with non-segmented genomes
that utilize cap-snatching. Bunyaviridae have segmented genomes; Filoviridae are filamentous; Orthomyxoviridae have segmented genomes and also use
cap-snatching but are influenza viruses.
🟢 2. A researcher is studying a bacteriophage that exhibits a unique replication strategy where the phage genome exists as a circular plasmid within the
host cell, replicating independently without integrating into the host chromosome. The phage can switch to a lytic cycle under conditions of host stress.
This phage is BEST described as:
A) Temperate phage undergoing lysogeny
B) Virulent phage undergoing lytic replication
C) Filamentous phage undergoing chronic infection
D) Satellite phage requiring a helper virus
✅ Correct Answer: A – Temperate phages can exist as episomes (plasmids) or integrate (prophage) and switch to lytic replication. Virulent phages only
undergo lytic replication; Filamentous phages cause chronic infections without lysis; Satellite phages require helper viruses.
🟢 3. A 45-year-old immunocompromised patient develops progressive multifocal leukoencephalopathy (PML). The causative virus, JC virus, belongs to the
family Polyomaviridae. Which of the following statements about JC virus replication is CORRECT?
A) It is a double-stranded DNA virus that uses host RNA polymerase II for transcription
B) It is a single-stranded RNA virus that replicates in the cytoplasm
C) It is a double-stranded DNA virus that encodes its own DNA-dependent RNA polymerase
D) It is a retrovirus that integrates into the host genome
✅ Correct Answer: A – JC virus is a dsDNA virus that relies on host RNA polymerase II for transcription. RNA viruses replicate in the cytoplasm; dsDNA
viruses do not typically encode their own RNA polymerase; Retroviruses integrate into the host genome.
🟢 4. A 28-year-old patient presents with fever, pharyngitis, and cervical lymphadenopathy. A Monospot test is positive. The causative virus, Epstein-Barr
virus (EBV), establishes latency in which of the following cell types?
A) Memory B cells
B) CD4+ T cells
C) CD8+ T cells
D) Natural killer cells
, ✅ Correct Answer: A – EBV establishes latency in memory B cells. It does not establish latency in T cells or NK cells; CD8+ T cells are the primary
immune response against EBV-infected cells.
🟢 5. A 60-year-old patient with a history of herpes zoster presents with persistent pain in the affected dermatome that has lasted for 3 months after the
rash has healed. This condition is known as postherpetic neuralgia. Which of the following is the MOST appropriate mechanism for the pathogenesis of this
condition?
A) Direct viral cytopathic effect on sensory neurons
B) Immune-mediated inflammation and nerve damage
C) Viral reactivation causing chronic inflammation
D) Latent viral genome expression in neurons causing altered pain signaling
✅ Correct Answer: D – Postherpetic neuralgia is thought to result from latent VZV genome expression in dorsal root ganglia, causing altered pain
signaling. Direct cytopathic effect and inflammation are acute; chronic reactivation is not typical.
🟢 6. A 35-year-old patient presents with fever, myalgias, and a maculopapular rash after returning from a trip to Brazil. The patient also reports
conjunctivitis and arthralgias. A serum sample is positive for Zika virus IgM antibodies. Which of the following is the MOST significant concern regarding
Zika virus infection in pregnant women?
A) Congenital heart defects
B) Microcephaly and other fetal brain abnormalities
C) Fetal hydrops
D) Premature rupture of membranes
✅ Correct Answer: B – Zika virus infection during pregnancy is associated with microcephaly and other fetal brain abnormalities. Congenital heart
defects, hydrops, and premature rupture are not specifically associated with Zika.
🟢 7. A 50-year-old patient with HIV/AIDS presents with fever, headache, and confusion. A lumbar puncture reveals encapsulated yeast cells. The patient is
diagnosed with cryptococcal meningitis. Which of the following virulence factors of Cryptococcus neoformans is MOST responsible for its ability to evade
the host immune response?
A) Production of melanin
B) Production of a polysaccharide capsule
C) Production of urease
D) Ability to grow at 37°C
✅ Correct Answer: B – The polysaccharide capsule is the primary virulence factor that inhibits phagocytosis and modulates the host immune response.
Melanin and urease contribute but are secondary; thermotolerance is important but not the primary immune evasion factor.
🟢 8. A 25-year-old patient presents with fever, headache, and a stiff neck. A lumbar puncture reveals Gram-negative diplococci in the CSF. The patient is
diagnosed with meningococcal meningitis. Which of the following vaccines provides protection against Neisseria meningitidis serogroups A, C, W, Y, and B?
A) Meningococcal conjugate vaccine (MCV4)
B) Meningococcal polysaccharide vaccine (MPSV4)
C) Serogroup B meningococcal vaccine (MenB)
D) All of the above in combination
✅ Correct Answer: A – MCV4 provides protection against serogroups A, C, W, and Y. MenB vaccine provides protection against serogroup B only.
MPSV4 also covers A, C, W, Y but is less immunogenic than MCV4.
🟢 9. A 40-year-old patient presents with a painless, ulcerated genital lesion. Dark-field microscopy reveals spirochetes. The patient is diagnosed with
primary syphilis. Which of the following is the MOST appropriate treatment for primary syphilis?
A) Azithromycin
B) Doxycycline
, C) Penicillin G benzathine
D) Ceftriaxone
✅ Correct Answer: C – Penicillin G benzathine is the treatment of choice for primary syphilis. Azithromycin is not recommended due to resistance;
Doxycycline is an alternative for penicillin-allergic patients but less effective; Ceftriaxone is an alternative but not first-line.
🟢 10. A 55-year-old patient presents with a fever, chills, and a productive cough with purulent sputum. A chest X-ray shows a cavitary lesion. A sputum
culture grows Klebsiella pneumoniae. Which of the following virulence factors is MOST associated with the "currant jelly" sputum produced by this
organism?
A) Capsular polysaccharide
B) Lipopolysaccharide (LPS)
C) Pili
D) Siderophores
✅ Correct Answer: A – The capsular polysaccharide is responsible for the thick, mucoid "currant jelly" sputum. LPS is an endotoxin; Pili are for adhesion;
Siderophores are for iron acquisition.
SECTION 2: VIROLOGY – Antiviral Therapy and Resistance
🟢 11. A 45-year-old patient with chronic hepatitis C is treated with a direct-acting antiviral (DAA) regimen. Which of the following mechanisms of action is
associated with sofosbuvir?
A) NS3/4A protease inhibitor
B) NS5A inhibitor
C) NS5B polymerase inhibitor (nucleotide analog)
D) NS5B polymerase inhibitor (non-nucleoside)
✅ Correct Answer: C – Sofosbuvir is a nucleotide analog that inhibits the NS5B RNA-dependent RNA polymerase. Glecaprevir/pibrentasvir are NS3/4A
and NS5A inhibitors; Dasabuvir is a non-nucleoside NS5B inhibitor.
🟢 12. A 60-year-old patient with HIV infection has a viral load of 50,000 copies/mL and a CD4 count of 150 cells/μL. The patient is started on a regimen of
tenofovir disoproxil fumarate, emtricitabine, and dolutegravir. Which of the following describes the mechanism of action of dolutegravir?
A) Nucleoside reverse transcriptase inhibitor (NRTI)
B) Non-nucleoside reverse transcriptase inhibitor (NNRTI)
C) Integrase strand transfer inhibitor (INSTI)
D) Protease inhibitor (PI)
✅ Correct Answer: C – Dolutegravir is an integrase strand transfer inhibitor. Tenofovir and emtricitabine are NRTIs; NNRTIs include efavirenz; Protease
inhibitors include darunavir.
🟢 13. A 50-year-old patient with influenza is prescribed oseltamivir. Which of the following describes the mechanism of action of oseltamivir?
A) Inhibition of the M2 ion channel
B) Inhibition of neuraminidase
C) Inhibition of hemagglutinin
D) Inhibition of RNA-dependent RNA polymerase
✅ Correct Answer: B – Oseltamivir inhibits neuraminidase, preventing viral release. Adamantanes inhibit M2 ion channels; Hemagglutinin is a target for
vaccines; Polymerase inhibitors (baloxavir) inhibit RNA-dependent RNA polymerase.
🟢 14. A 55-year-old patient with herpes simplex virus (HSV) infection develops a lesion that is unresponsive to acyclovir. A viral culture reveals a thymidine
kinase (TK)-deficient mutant. Which of the following is the MOST appropriate alternative treatment?
, A) Valacyclovir
B) Famciclovir
C) Foscarnet
D) Penciclovir
✅ Correct Answer: C – Foscarnet does not require TK for activation and is effective against acyclovir-resistant HSV. Valacyclovir, famciclovir, and
penciclovir require TK and would not be effective against TK-deficient mutants.
🟢 15. A 40-year-old patient with chronic hepatitis B is treated with entecavir. Which of the following is the mechanism of action of entecavir?
A) Inhibition of hepatitis B virus reverse transcriptase
B) Inhibition of hepatitis B virus protease
C) Inhibition of hepatitis B virus DNA polymerase
D) Inhibition of hepatitis B virus entry
✅ Correct Answer: C – Entecavir is a nucleoside analog that inhibits HBV DNA polymerase. It does not inhibit reverse transcriptase (HIV drugs),
protease, or viral entry.
SECTION 3: MYCOLOGY – Advanced Antifungal Therapy and Resistance
🟢 16. A 65-year-old patient with invasive aspergillosis is treated with voriconazole. Which of the following describes the mechanism of action of
voriconazole?
A) Inhibition of β-1,3-glucan synthase
B) Inhibition of ergosterol synthesis via lanosterol 14α-demethylase
C) Binding to ergosterol in the cell membrane
D) Inhibition of DNA synthesis
✅ Correct Answer: B – Voriconazole is an azole that inhibits lanosterol 14α-demethylase (CYP51), blocking ergosterol synthesis. Caspofungin inhibits
β-1,3-glucan synthase; Amphotericin B binds ergosterol; Flucytosine inhibits DNA synthesis.
🟢 17. A 50-year-old patient with candidemia is treated with caspofungin. Which of the following describes the mechanism of action of caspofungin?
A) Inhibition of ergosterol synthesis
B) Inhibition of β-1,3-glucan synthase
C) Binding to ergosterol in the cell membrane
D) Inhibition of DNA synthesis
✅ Correct Answer: B – Caspofungin is an echinocandin that inhibits β-1,3-glucan synthase, disrupting the fungal cell wall. Azoles inhibit ergosterol
synthesis; Amphotericin B binds ergosterol; Flucytosine inhibits DNA synthesis.
🟢 18. A 45-year-old patient with mucormycosis is treated with liposomal amphotericin B. Which of the following is the MOST appropriate alternative
therapy if the patient cannot tolerate amphotericin B?
A) Voriconazole
B) Isavuconazole
C) Caspofungin
D) Fluconazole
✅ Correct Answer: B – Isavuconazole is an alternative for mucormycosis (zygomycosis). Voriconazole is not effective against Mucorales; Caspofungin is
not effective; Fluconazole is not effective.
🟢 19. A 60-year-old patient with onychomycosis is treated with terbinafine. Which of the following describes the mechanism of action of terbinafine?
Advanced/Hard Difficulty | College/University Level | 150 Questions
Comprehensive Coverage: Virology, Mycology, Parasitology, Epidemiology, Diagnostics, Immunology, Antimicrobial
Therapy, and Emerging Diseases
SECTION 1: VIROLOGY – Advanced Molecular Mechanisms and Pathogenesis
🟢 1. A novel virus is isolated from a patient with hemorrhagic fever in South America. Electron microscopy reveals a spherical, enveloped virion with a
helical nucleocapsid and a negative-sense single-stranded RNA genome that is non-segmented. The virus encodes a unique "capping" enzyme that steals
5' caps from host mRNAs (cap-snatching). Which viral family does this virus MOST likely belong to?
A) Arenaviridae
B) Bunyaviridae
C) Filoviridae
D) Orthomyxoviridae
✅ Correct Answer: A – Arenaviruses (e.g., Lassa virus, Junin virus) are enveloped, helical, negative-sense ssRNA viruses with non-segmented genomes
that utilize cap-snatching. Bunyaviridae have segmented genomes; Filoviridae are filamentous; Orthomyxoviridae have segmented genomes and also use
cap-snatching but are influenza viruses.
🟢 2. A researcher is studying a bacteriophage that exhibits a unique replication strategy where the phage genome exists as a circular plasmid within the
host cell, replicating independently without integrating into the host chromosome. The phage can switch to a lytic cycle under conditions of host stress.
This phage is BEST described as:
A) Temperate phage undergoing lysogeny
B) Virulent phage undergoing lytic replication
C) Filamentous phage undergoing chronic infection
D) Satellite phage requiring a helper virus
✅ Correct Answer: A – Temperate phages can exist as episomes (plasmids) or integrate (prophage) and switch to lytic replication. Virulent phages only
undergo lytic replication; Filamentous phages cause chronic infections without lysis; Satellite phages require helper viruses.
🟢 3. A 45-year-old immunocompromised patient develops progressive multifocal leukoencephalopathy (PML). The causative virus, JC virus, belongs to the
family Polyomaviridae. Which of the following statements about JC virus replication is CORRECT?
A) It is a double-stranded DNA virus that uses host RNA polymerase II for transcription
B) It is a single-stranded RNA virus that replicates in the cytoplasm
C) It is a double-stranded DNA virus that encodes its own DNA-dependent RNA polymerase
D) It is a retrovirus that integrates into the host genome
✅ Correct Answer: A – JC virus is a dsDNA virus that relies on host RNA polymerase II for transcription. RNA viruses replicate in the cytoplasm; dsDNA
viruses do not typically encode their own RNA polymerase; Retroviruses integrate into the host genome.
🟢 4. A 28-year-old patient presents with fever, pharyngitis, and cervical lymphadenopathy. A Monospot test is positive. The causative virus, Epstein-Barr
virus (EBV), establishes latency in which of the following cell types?
A) Memory B cells
B) CD4+ T cells
C) CD8+ T cells
D) Natural killer cells
, ✅ Correct Answer: A – EBV establishes latency in memory B cells. It does not establish latency in T cells or NK cells; CD8+ T cells are the primary
immune response against EBV-infected cells.
🟢 5. A 60-year-old patient with a history of herpes zoster presents with persistent pain in the affected dermatome that has lasted for 3 months after the
rash has healed. This condition is known as postherpetic neuralgia. Which of the following is the MOST appropriate mechanism for the pathogenesis of this
condition?
A) Direct viral cytopathic effect on sensory neurons
B) Immune-mediated inflammation and nerve damage
C) Viral reactivation causing chronic inflammation
D) Latent viral genome expression in neurons causing altered pain signaling
✅ Correct Answer: D – Postherpetic neuralgia is thought to result from latent VZV genome expression in dorsal root ganglia, causing altered pain
signaling. Direct cytopathic effect and inflammation are acute; chronic reactivation is not typical.
🟢 6. A 35-year-old patient presents with fever, myalgias, and a maculopapular rash after returning from a trip to Brazil. The patient also reports
conjunctivitis and arthralgias. A serum sample is positive for Zika virus IgM antibodies. Which of the following is the MOST significant concern regarding
Zika virus infection in pregnant women?
A) Congenital heart defects
B) Microcephaly and other fetal brain abnormalities
C) Fetal hydrops
D) Premature rupture of membranes
✅ Correct Answer: B – Zika virus infection during pregnancy is associated with microcephaly and other fetal brain abnormalities. Congenital heart
defects, hydrops, and premature rupture are not specifically associated with Zika.
🟢 7. A 50-year-old patient with HIV/AIDS presents with fever, headache, and confusion. A lumbar puncture reveals encapsulated yeast cells. The patient is
diagnosed with cryptococcal meningitis. Which of the following virulence factors of Cryptococcus neoformans is MOST responsible for its ability to evade
the host immune response?
A) Production of melanin
B) Production of a polysaccharide capsule
C) Production of urease
D) Ability to grow at 37°C
✅ Correct Answer: B – The polysaccharide capsule is the primary virulence factor that inhibits phagocytosis and modulates the host immune response.
Melanin and urease contribute but are secondary; thermotolerance is important but not the primary immune evasion factor.
🟢 8. A 25-year-old patient presents with fever, headache, and a stiff neck. A lumbar puncture reveals Gram-negative diplococci in the CSF. The patient is
diagnosed with meningococcal meningitis. Which of the following vaccines provides protection against Neisseria meningitidis serogroups A, C, W, Y, and B?
A) Meningococcal conjugate vaccine (MCV4)
B) Meningococcal polysaccharide vaccine (MPSV4)
C) Serogroup B meningococcal vaccine (MenB)
D) All of the above in combination
✅ Correct Answer: A – MCV4 provides protection against serogroups A, C, W, and Y. MenB vaccine provides protection against serogroup B only.
MPSV4 also covers A, C, W, Y but is less immunogenic than MCV4.
🟢 9. A 40-year-old patient presents with a painless, ulcerated genital lesion. Dark-field microscopy reveals spirochetes. The patient is diagnosed with
primary syphilis. Which of the following is the MOST appropriate treatment for primary syphilis?
A) Azithromycin
B) Doxycycline
, C) Penicillin G benzathine
D) Ceftriaxone
✅ Correct Answer: C – Penicillin G benzathine is the treatment of choice for primary syphilis. Azithromycin is not recommended due to resistance;
Doxycycline is an alternative for penicillin-allergic patients but less effective; Ceftriaxone is an alternative but not first-line.
🟢 10. A 55-year-old patient presents with a fever, chills, and a productive cough with purulent sputum. A chest X-ray shows a cavitary lesion. A sputum
culture grows Klebsiella pneumoniae. Which of the following virulence factors is MOST associated with the "currant jelly" sputum produced by this
organism?
A) Capsular polysaccharide
B) Lipopolysaccharide (LPS)
C) Pili
D) Siderophores
✅ Correct Answer: A – The capsular polysaccharide is responsible for the thick, mucoid "currant jelly" sputum. LPS is an endotoxin; Pili are for adhesion;
Siderophores are for iron acquisition.
SECTION 2: VIROLOGY – Antiviral Therapy and Resistance
🟢 11. A 45-year-old patient with chronic hepatitis C is treated with a direct-acting antiviral (DAA) regimen. Which of the following mechanisms of action is
associated with sofosbuvir?
A) NS3/4A protease inhibitor
B) NS5A inhibitor
C) NS5B polymerase inhibitor (nucleotide analog)
D) NS5B polymerase inhibitor (non-nucleoside)
✅ Correct Answer: C – Sofosbuvir is a nucleotide analog that inhibits the NS5B RNA-dependent RNA polymerase. Glecaprevir/pibrentasvir are NS3/4A
and NS5A inhibitors; Dasabuvir is a non-nucleoside NS5B inhibitor.
🟢 12. A 60-year-old patient with HIV infection has a viral load of 50,000 copies/mL and a CD4 count of 150 cells/μL. The patient is started on a regimen of
tenofovir disoproxil fumarate, emtricitabine, and dolutegravir. Which of the following describes the mechanism of action of dolutegravir?
A) Nucleoside reverse transcriptase inhibitor (NRTI)
B) Non-nucleoside reverse transcriptase inhibitor (NNRTI)
C) Integrase strand transfer inhibitor (INSTI)
D) Protease inhibitor (PI)
✅ Correct Answer: C – Dolutegravir is an integrase strand transfer inhibitor. Tenofovir and emtricitabine are NRTIs; NNRTIs include efavirenz; Protease
inhibitors include darunavir.
🟢 13. A 50-year-old patient with influenza is prescribed oseltamivir. Which of the following describes the mechanism of action of oseltamivir?
A) Inhibition of the M2 ion channel
B) Inhibition of neuraminidase
C) Inhibition of hemagglutinin
D) Inhibition of RNA-dependent RNA polymerase
✅ Correct Answer: B – Oseltamivir inhibits neuraminidase, preventing viral release. Adamantanes inhibit M2 ion channels; Hemagglutinin is a target for
vaccines; Polymerase inhibitors (baloxavir) inhibit RNA-dependent RNA polymerase.
🟢 14. A 55-year-old patient with herpes simplex virus (HSV) infection develops a lesion that is unresponsive to acyclovir. A viral culture reveals a thymidine
kinase (TK)-deficient mutant. Which of the following is the MOST appropriate alternative treatment?
, A) Valacyclovir
B) Famciclovir
C) Foscarnet
D) Penciclovir
✅ Correct Answer: C – Foscarnet does not require TK for activation and is effective against acyclovir-resistant HSV. Valacyclovir, famciclovir, and
penciclovir require TK and would not be effective against TK-deficient mutants.
🟢 15. A 40-year-old patient with chronic hepatitis B is treated with entecavir. Which of the following is the mechanism of action of entecavir?
A) Inhibition of hepatitis B virus reverse transcriptase
B) Inhibition of hepatitis B virus protease
C) Inhibition of hepatitis B virus DNA polymerase
D) Inhibition of hepatitis B virus entry
✅ Correct Answer: C – Entecavir is a nucleoside analog that inhibits HBV DNA polymerase. It does not inhibit reverse transcriptase (HIV drugs),
protease, or viral entry.
SECTION 3: MYCOLOGY – Advanced Antifungal Therapy and Resistance
🟢 16. A 65-year-old patient with invasive aspergillosis is treated with voriconazole. Which of the following describes the mechanism of action of
voriconazole?
A) Inhibition of β-1,3-glucan synthase
B) Inhibition of ergosterol synthesis via lanosterol 14α-demethylase
C) Binding to ergosterol in the cell membrane
D) Inhibition of DNA synthesis
✅ Correct Answer: B – Voriconazole is an azole that inhibits lanosterol 14α-demethylase (CYP51), blocking ergosterol synthesis. Caspofungin inhibits
β-1,3-glucan synthase; Amphotericin B binds ergosterol; Flucytosine inhibits DNA synthesis.
🟢 17. A 50-year-old patient with candidemia is treated with caspofungin. Which of the following describes the mechanism of action of caspofungin?
A) Inhibition of ergosterol synthesis
B) Inhibition of β-1,3-glucan synthase
C) Binding to ergosterol in the cell membrane
D) Inhibition of DNA synthesis
✅ Correct Answer: B – Caspofungin is an echinocandin that inhibits β-1,3-glucan synthase, disrupting the fungal cell wall. Azoles inhibit ergosterol
synthesis; Amphotericin B binds ergosterol; Flucytosine inhibits DNA synthesis.
🟢 18. A 45-year-old patient with mucormycosis is treated with liposomal amphotericin B. Which of the following is the MOST appropriate alternative
therapy if the patient cannot tolerate amphotericin B?
A) Voriconazole
B) Isavuconazole
C) Caspofungin
D) Fluconazole
✅ Correct Answer: B – Isavuconazole is an alternative for mucormycosis (zygomycosis). Voriconazole is not effective against Mucorales; Caspofungin is
not effective; Fluconazole is not effective.
🟢 19. A 60-year-old patient with onychomycosis is treated with terbinafine. Which of the following describes the mechanism of action of terbinafine?
