Microbiology Fortis Final
1. Which structure is found in prokaryotic cells but not in eukaryotic cells?
A. Nucleus
B. Mitochondria
C. Peptidoglycan cell wall
D. Endoplasmic reticulum
Answer: C – Prokaryotes have a peptidoglycan cell wall; eukaryotic cells do not.
2. Which of the following is a Gram-negative bacterium characteristic?
A. Thick peptidoglycan layer
B. Teichoic acids in the cell wall
C. Outer membrane containing lipopolysaccharide (LPS)
D. No periplasmic space
Answer: C – Gram-negative bacteria have an outer membrane with LPS and a thin
peptidoglycan layer.
3. Which staining technique is used to identify Mycobacterium tuberculosis?
A. Gram stain
B. Acid-fast stain
C. Capsule stain
D. Endospore stain
Answer: B – Acid-fast stain detects mycolic acid in Mycobacterium cell walls.
,4. Which phase of the bacterial growth curve shows the highest rate of binary
fission?
A. Lag phase
B. Log (exponential) phase
C. Stationary phase
D. Death phase
Answer: B – The log phase is when cells divide rapidly.
5. Which microorganism causes strep throat?
A. Staphylococcus aureus
B. Escherichia coli
C. Streptococcus pyogenes
D. Klebsiella pneumoniae
Answer: C – S. pyogenes causes pharyngitis (strep throat).
6. Which type of immunity is acquired after recovering from an infection?
A. Natural active immunity
B. Natural passive immunity
C. Artificial active immunity
D. Artificial passive immunity
Answer: A – Infection stimulates active immunity through memory cell formation.
7. Which of the following diseases is caused by a protozoan?
A. Tuberculosis
B. Malaria
C. Tetanus
D. Lyme disease
Answer: B – Malaria is caused by Plasmodium species (protozoa).
, 8. Which viral structure is composed of phospholipids and surrounds some viruses?
A. Capsid
B. Envelope
C. Genome
D. Nucleoid
Answer: B – The envelope is a lipid bilayer derived from the host cell membrane.
9. What is the primary mode of transmission for hepatitis B virus (HBV)?
A. Fecal–oral
B. Respiratory droplets
C. Blood and body fluids
D. Vector-borne
Answer: C – HBV is transmitted through blood, sexual contact, and perinatal
exposure.
10. Which antibiotic inhibits bacterial protein synthesis by binding to the 30S
ribosomal subunit?
A. Penicillin
B. Tetracycline
C. Vancomycin
D. Rifampin
Answer: B – Tetracycline targets the 30S ribosomal subunit.
Part B – Short Answer
11. Define “opportunistic pathogen.”
Answer: A microorganism that does not normally cause disease but can cause illness
when the host’s immune system is weakened or when it enters an unusual location.
1. Which structure is found in prokaryotic cells but not in eukaryotic cells?
A. Nucleus
B. Mitochondria
C. Peptidoglycan cell wall
D. Endoplasmic reticulum
Answer: C – Prokaryotes have a peptidoglycan cell wall; eukaryotic cells do not.
2. Which of the following is a Gram-negative bacterium characteristic?
A. Thick peptidoglycan layer
B. Teichoic acids in the cell wall
C. Outer membrane containing lipopolysaccharide (LPS)
D. No periplasmic space
Answer: C – Gram-negative bacteria have an outer membrane with LPS and a thin
peptidoglycan layer.
3. Which staining technique is used to identify Mycobacterium tuberculosis?
A. Gram stain
B. Acid-fast stain
C. Capsule stain
D. Endospore stain
Answer: B – Acid-fast stain detects mycolic acid in Mycobacterium cell walls.
,4. Which phase of the bacterial growth curve shows the highest rate of binary
fission?
A. Lag phase
B. Log (exponential) phase
C. Stationary phase
D. Death phase
Answer: B – The log phase is when cells divide rapidly.
5. Which microorganism causes strep throat?
A. Staphylococcus aureus
B. Escherichia coli
C. Streptococcus pyogenes
D. Klebsiella pneumoniae
Answer: C – S. pyogenes causes pharyngitis (strep throat).
6. Which type of immunity is acquired after recovering from an infection?
A. Natural active immunity
B. Natural passive immunity
C. Artificial active immunity
D. Artificial passive immunity
Answer: A – Infection stimulates active immunity through memory cell formation.
7. Which of the following diseases is caused by a protozoan?
A. Tuberculosis
B. Malaria
C. Tetanus
D. Lyme disease
Answer: B – Malaria is caused by Plasmodium species (protozoa).
, 8. Which viral structure is composed of phospholipids and surrounds some viruses?
A. Capsid
B. Envelope
C. Genome
D. Nucleoid
Answer: B – The envelope is a lipid bilayer derived from the host cell membrane.
9. What is the primary mode of transmission for hepatitis B virus (HBV)?
A. Fecal–oral
B. Respiratory droplets
C. Blood and body fluids
D. Vector-borne
Answer: C – HBV is transmitted through blood, sexual contact, and perinatal
exposure.
10. Which antibiotic inhibits bacterial protein synthesis by binding to the 30S
ribosomal subunit?
A. Penicillin
B. Tetracycline
C. Vancomycin
D. Rifampin
Answer: B – Tetracycline targets the 30S ribosomal subunit.
Part B – Short Answer
11. Define “opportunistic pathogen.”
Answer: A microorganism that does not normally cause disease but can cause illness
when the host’s immune system is weakened or when it enters an unusual location.
