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: Bacteria multiply most rapidly during which growth phase?
A) Death phase
B) Stationary phase
C) Log phase
D) Lag phase
✅ Correct Answer: C
Explanation: The log phase is characterized by exponential bacterial replication under optimal conditions.
Q: Gram-positive bacteria retain the primary stain due to
A) Thick peptidoglycan
B) Thin peptidoglycan
C) Capsule
D) Outer membrane
✅ Correct Answer: A
Explanation: The thick peptidoglycan layer in Gram-positive bacteria traps the crystal violet-iodine complex during staining.
Q: Mycobacterium tuberculosis is best stained using
A) Acid-fast stain
B) Simple stain
C) Gram stain
D) Endospore stain
✅ Correct Answer: A
Explanation: The acid-fast stain is used due to the high lipid content in the cell wall of Mycobacterium tuberculosis.
Q: Viruses differ from bacteria because they
A) Have ribosomes
B) Lack a nucleus
C) Can reproduce independently
D) Are obligate intracellular parasites
✅ Correct Answer: D
Explanation: Viruses must invade host cells to replicate, making them obligate intracellular parasites.
Q: Fungal infections in humans are typically caused by
A) Helminths
B) Eukaryotic organisms
C) Algae
D) Protozoa
✅ Correct Answer: B
Explanation: Fungi are eukaryotic organisms capable of causing systemic and superficial infections.