Examination questions and verified
answers with rationale
1. Which branch of science studies microorganisms?
A. Pathology
B. Microbiology
C. Physiology
D. Histology
Answer: B. Microbiology
Rationale: Microbiology is the scientific study of
microorganisms such as bacteria, viruses, fungi, and
protozoa.
2. Which microorganism lacks a true nucleus?
A. Fungus
B. Protozoan
C. Bacterium
D. Alga
Answer: C. Bacterium
Rationale: Bacteria are prokaryotic organisms that do not
possess a membrane-bound nucleus.
,3. Which structure helps many bacteria move?
A. Capsule
B. Cell wall
C. Flagellum
D. Ribosome
Answer: C. Flagellum
Rationale: Flagella are whip-like structures that provide
bacterial motility.
4. Which bacterial structure protects against drying and
assists in attachment to surfaces?
A. Capsule
B. Nucleus
C. Mitochondrion
D. Endoplasmic reticulum
Answer: A. Capsule
Rationale: The capsule protects bacteria from desiccation and
enhances attachment to host tissues.
5. Which stain is commonly used to classify bacteria into
Gram-positive and Gram-negative groups?
A. Ziehl-Neelsen stain
B. Gram stain
C. Wright stain
D. India ink stain
,Answer: B. Gram stain
Rationale: The Gram stain differentiates bacteria based on
differences in cell wall composition.
6. Gram-positive bacteria appear which colour after Gram
staining?
A. Pink
B. Red
C. Purple
D. Orange
Answer: C. Purple
Rationale: Gram-positive bacteria retain the crystal violet
stain because of their thick peptidoglycan cell wall.
7. Which microorganism is an obligate intracellular parasite?
A. Bacterium
B. Fungus
C. Virus
D. Protozoan
Answer: C. Virus
Rationale: Viruses require living host cells to reproduce
because they cannot replicate independently.
8. Which microorganism commonly causes oral thrush?
, A. Candida albicans
B. Escherichia coli
C. Influenza virus
D. Plasmodium falciparum
Answer: A. Candida albicans
Rationale: Candida albicans is a yeast responsible for oral and
vaginal candidiasis.
9. Which microorganism causes malaria?
A. Giardia lamblia
B. Plasmodium falciparum
C. Entamoeba histolytica
D. Toxoplasma gondii
Answer: B. Plasmodium falciparum
Rationale: Plasmodium species are protozoa transmitted by
female Anopheles mosquitoes and cause malaria.
10. Which microorganism is most commonly associated with
pulmonary tuberculosis?
A. Staphylococcus aureus
B. Mycobacterium tuberculosis
C. Streptococcus pneumoniae
D. Escherichia coli
Answer: B. Mycobacterium tuberculosis