mehari biol 3200-final exam UPDATED ACTUAL Exam Questions and CORRECT
Answers.200 practice questions and with rationales
Section 1: Course & Instructor Information
Question 1: Dr. Mehari's country of origin is:
A. Ethiopia, East Africa
B. Eritrea, East Africa
C. Sudan, North Africa
D. Somalia, East Africa
Answer: B
Rationale: According to course materials, Dr. Mehari's country of origin is Eritrea,
East Africa .
Question 2: Who built the first microscope and was the first to observe single-
celled microbes?
A. Robert Hooke
B. Louis Pasteur
C. Antoine van Leeuwenhoek
D. Robert Koch
,Answer: C
Rationale: Antoine van Leeuwenhoek built single-lens magnifiers with sample
holders and focus adjustments, and he was the first to observe single-celled
microbes .
Section 2: Bacterial Genetics & Pathogenesis
Question 3: Why is antibiotic treatment of Gram-negative bacteria NOT always a
good idea?
A. They are naturally resistant to all antibiotics
B. It can result in release of endotoxin
C. They have no cell wall to target
D. Antibiotics cannot penetrate their capsule
Answer: B
Rationale: When Gram-negative bacteria are killed by antibiotics, they release
lipopolysaccharide (LPS/endotoxin) from their outer membrane, which can trigger
a severe inflammatory response (septic shock) .
Question 4: The ability to survive in the harsh environment of the phagolysosome
is a virulence factor produced by:
,A. Staphylococcus aureus
B. Escherichia coli
C. Coxiella burnetii
D. Pseudomonas aeruginosa
Answer: C
Rationale: Coxiella burnetii, the causative agent of Q fever, has evolved
mechanisms to survive and replicate within the phagolysosome of host
macrophages .
Question 5: What type of toxin is the Shiga toxin of E. coli O157:H7?
A. Membrane disruptor
B. Superantigen
C. Protein synthesis inhibitor
D. ADP-ribosylating toxin
Answer: C
Rationale: Shiga toxin inhibits protein synthesis by removing an adenine residue
from the 28S rRNA of the 60S ribosomal subunit, preventing elongation factor
binding .
, Question 6: Match the organism with its virulence factor:
Pseudomonas aeruginosa
Yersinia pestis
Bordetella pertussis
Staphylococcus aureus
A. Type II secretion system / Type III secretion system / Type IV secretion system /
Protein A
B. Type IV secretion system / Type II secretion system / Type III secretion system /
Capsule
C. Type I secretion system / Type V secretion system / Type II secretion system /
Shiga toxin
D. Protein A / Capsule / Type III secretion system / Type II secretion system
Answer: A
Answers.200 practice questions and with rationales
Section 1: Course & Instructor Information
Question 1: Dr. Mehari's country of origin is:
A. Ethiopia, East Africa
B. Eritrea, East Africa
C. Sudan, North Africa
D. Somalia, East Africa
Answer: B
Rationale: According to course materials, Dr. Mehari's country of origin is Eritrea,
East Africa .
Question 2: Who built the first microscope and was the first to observe single-
celled microbes?
A. Robert Hooke
B. Louis Pasteur
C. Antoine van Leeuwenhoek
D. Robert Koch
,Answer: C
Rationale: Antoine van Leeuwenhoek built single-lens magnifiers with sample
holders and focus adjustments, and he was the first to observe single-celled
microbes .
Section 2: Bacterial Genetics & Pathogenesis
Question 3: Why is antibiotic treatment of Gram-negative bacteria NOT always a
good idea?
A. They are naturally resistant to all antibiotics
B. It can result in release of endotoxin
C. They have no cell wall to target
D. Antibiotics cannot penetrate their capsule
Answer: B
Rationale: When Gram-negative bacteria are killed by antibiotics, they release
lipopolysaccharide (LPS/endotoxin) from their outer membrane, which can trigger
a severe inflammatory response (septic shock) .
Question 4: The ability to survive in the harsh environment of the phagolysosome
is a virulence factor produced by:
,A. Staphylococcus aureus
B. Escherichia coli
C. Coxiella burnetii
D. Pseudomonas aeruginosa
Answer: C
Rationale: Coxiella burnetii, the causative agent of Q fever, has evolved
mechanisms to survive and replicate within the phagolysosome of host
macrophages .
Question 5: What type of toxin is the Shiga toxin of E. coli O157:H7?
A. Membrane disruptor
B. Superantigen
C. Protein synthesis inhibitor
D. ADP-ribosylating toxin
Answer: C
Rationale: Shiga toxin inhibits protein synthesis by removing an adenine residue
from the 28S rRNA of the 60S ribosomal subunit, preventing elongation factor
binding .
, Question 6: Match the organism with its virulence factor:
Pseudomonas aeruginosa
Yersinia pestis
Bordetella pertussis
Staphylococcus aureus
A. Type II secretion system / Type III secretion system / Type IV secretion system /
Protein A
B. Type IV secretion system / Type II secretion system / Type III secretion system /
Capsule
C. Type I secretion system / Type V secretion system / Type II secretion system /
Shiga toxin
D. Protein A / Capsule / Type III secretion system / Type II secretion system
Answer: A
