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 function of an autoclave is to
A) Sterilize using dry heat
B) Sterilize using steam under pressure
C) Disinfect using alcohol
D) Kill viruses only
✅ Correct Answer: B
Explanation: Autoclaving uses moist heat under pressure to effectively sterilize equipment and media.
Q: Botulinum toxin acts by
A) Increasing neurotransmitter release
B) Damaging DNA
C) Inhibiting protein synthesis
D) Blocking acetylcholine release
✅ Correct Answer: D
Explanation: Botulinum toxin blocks acetylcholine release, causing flaccid paralysis.
Q: MacConkey agar is selective for
A) Fungi
B) Gram-negative bacteria
C) Gram-positive bacteria
D) Viruses
✅ Correct Answer: B
Explanation: MacConkey agar contains bile salts and crystal violet, which inhibit Gram-positive organisms and allow Gram-negative growth.
Q: A lytic bacteriophage
A) Kills the host cell
B) Converts bacteria into spores
C) Forms a symbiotic relationship
D) Integrates into the host genome
✅ Correct Answer: A
Explanation: Lytic phages infect bacteria and rapidly lyse the host cell after viral replication.
Q: The test used to detect syphilis antibodies is the
A) Widal test
B) Tuberculin test
C) ELISA for HIV
D) VDRL test
✅ Correct Answer: D
Explanation: The VDRL (Venereal Disease Research Laboratory) test screens for antibodies produced in response to syphilis infection.