Microbiology MCQs
Microbiology MCQs challenge students to identify pathogens, understand microbial physiology, and master infection control protocols. These questions span bacteriology, virology, mycology, parasitology, and immunology. Suitable for exams like MDCAT, FCPS, NTS, and USMLE, these quizzes improve both academic knowledge and clinical readiness.
Q: Fever, rash, and Koplik spots are characteristic of
A) Chickenpox
B) Measles
C) Influenza
D) Rubella
✅ Correct Answer: B
Explanation: Measles presents with Koplik spots in the mouth, followed by a widespread rash and high fever.
Q: Bacteriophages are viruses that infect
A) Fungi
B) Protozoa
C) Bacteria
D) Animals
✅ Correct Answer: C
Explanation: Bacteriophages are specialized viruses that infect and replicate within bacterial cells.
Q: Disinfectants are primarily used on
A) Inanimate surfaces
B) Internal organs
C) Human tissues
D) Living cells
✅ Correct Answer: A
Explanation: Disinfectants destroy microorganisms on non-living objects and surfaces to prevent infection.
Q: The mode of transmission for Entamoeba histolytica is through
A) Skin penetration
B) Airborne droplets
C) Insect vectors
D) Contaminated food or water
✅ Correct Answer: D
Explanation: Entamoeba histolytica is spread via ingestion of cysts in contaminated food or water.
Q: A helminthic infection caused by ingestion of undercooked pork is
A) Ascariasis
B) Trichinellosis
C) Schistosomiasis
D) Filariasis
✅ Correct Answer: B
Explanation: Trichinella spiralis causes trichinellosis, often acquired from eating raw or undercooked pork.
Q: The test used to differentiate lactose-fermenting from non-lactose fermenting bacteria is
A) MacConkey agar
B) Blood agar
C) Chocolate agar
D) Mannitol salt agar
✅ Correct Answer: A
Explanation: MacConkey agar indicates lactose fermentation through colony color changes due to pH shifts.
Q: The toxin responsible for diphtheria is produced by
A) Streptococcus pneumoniae
B) Haemophilus influenzae
C) Corynebacterium diphtheriae
D) Neisseria meningitidis
✅ Correct Answer: C
Explanation: Corynebacterium diphtheriae produces an exotoxin that inhibits protein synthesis, causing severe respiratory illness.
Q: The major difference between prokaryotes and eukaryotes is the absence of
A) Nucleus
B) DNA
C) Cell wall
D) Ribosomes
✅ Correct Answer: A
Explanation: Prokaryotic cells lack a membrane-bound nucleus, distinguishing them from eukaryotic cells.
Q: The common cold is most often caused by
A) Coronavirus
B) Influenza virus
C) Rhinovirus
D) Adenovirus
✅ Correct Answer: C
Explanation: Rhinoviruses are the most frequent cause of the common cold, particularly in temperate climates.
Q: A positive India ink preparation suggests the presence of
A) Cryptococcus neoformans
B) Aspergillus fumigatus
C) Candida albicans
D) Histoplasma capsulatum
✅ Correct Answer: A
Explanation: Cryptococcus neoformans has a thick capsule that appears as a clear halo on India ink stain.