Microbiology MCQs
Microbiology MCQs cover bacteriology, virology, mycology, parasitology, and immunology, testing pathogen identification, microbial physiology, and infection control. Ideal for MDCAT, FCPS, NTS, and USMLE preparation, these quizzes boost academic knowledge, clinical skills, and exam success.
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.