VERSION 1 QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025
1. What structure do bacteria use to move?
A. Ribosomes
B. Pili
C. Flagella
D. Capsule
Flagella are tail-like structures that rotate to allow motility in
bacteria.
2. Which stain is used to differentiate bacterial species into Gram-
positive and Gram-negative?
A. Acid-fast stain
B. Capsule stain
C. Endospore stain
, D. Gram stain
The Gram stain differentiates based on cell wall composition:
peptidoglycan-rich walls retain crystal violet (Gram-positive).
3. Which of the following organisms is a prokaryote?
A. Escherichia coli
B. Saccharomyces cerevisiae
C. Amoeba proteus
D. Giardia lamblia
E. coli is a bacterium and lacks a nucleus, classifying it as a
prokaryote.
4. What type of microorganism causes tuberculosis?
A. Virus
B. Fungus
C. Bacterium
D. Protozoan
Mycobacterium tuberculosis is a bacterium responsible for
tuberculosis.
5. Which part of the bacterial cell is targeted by penicillin?
A. Ribosome
B. Cell wall
C. Plasma membrane
D. Nucleoid
, Penicillin interferes with peptidoglycan synthesis, weakening the
bacterial cell wall.
6. What is the term for bacteria that require oxygen to survive?
A. Facultative anaerobes
B. Aerotolerant anaerobes
C. Obligate aerobes
D. Obligate anaerobes
Obligate aerobes need oxygen for survival and growth.
7. Which microbial structure is involved in adherence to surfaces?
A. Fimbriae
B. Endospore
C. Nucleoid
D. Ribosome
Fimbriae are short hair-like structures that aid in attachment to host
tissues.
8. The time between infection and the appearance of symptoms is
called:
A. Prodromal period
B. Period of illness
C. Incubation period
D. Convalescence
The incubation period is the time from exposure to a pathogen until
symptoms appear.
, 9. What kind of immunity results from vaccination?
A. Natural active
B. Natural passive
C. Artificial passive
D. Artificial active
Vaccines stimulate the immune system to produce antibodies, which
is artificial active immunity.
10. What is the function of an endospore in bacteria?
A. Energy production
B. Survival under harsh conditions
C. DNA replication
D. Antibiotic resistance
Endospores are dormant structures that help bacteria survive
extreme conditions.
11. Which organism is known for causing strep throat?
A. Staphylococcus aureus
B. Escherichia coli
C. Streptococcus pyogenes
D. Neisseria meningitidis
Streptococcus pyogenes is the causative agent of strep throat.
12. What type of microscope provides the highest magnification and
resolution?
A. Compound light microscope