BIOL 271 MICROBIOLOGY W/ LAB MODULE 4 EXAM REVIEW | LOCKDOWN BROWSER | PORTAGE
LEARNING | 250 QUESTIONS
Questions 1–250
#### SECTION 1: BACTERIAL CELL STRUCTURE & FUNCTION (Questions 1–50)
1. Which of the following is a distinguishing feature of prokaryotic cells compared to eukaryotic
cells?
A) Presence of a nucleus
B) Lack of membrane-bound organelles
C) Presence of mitochondria
D) Presence of endoplasmic reticulum
Answer B: Lack of membrane-bound organelles
Rationale: Prokaryotic cells lack membrane-bound organelles, including a nucleus, mitochondria, and
endoplasmic reticulum.
2. The bacterial cell wall is composed primarily of:
A) Chitin
B) Cellulose
C) Peptidoglycan
D) Lipopolysaccharide
Answer C: Peptidoglycan
Rationale: Bacterial cell walls contain peptidoglycan, a polymer of N-acetylglucosamine and N-
acetylmuramic acid.
3. Gram-positive bacteria have a cell wall that is:
A) Thick and composed of multiple layers of peptidoglycan
B) Thin with an outer membrane
C) Composed only of lipopolysaccharide
D) Lacking peptidoglycan
Answer A: Thick and composed of multiple layers of peptidoglycan
,Rationale: Gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet-iodine
complex.
4. Gram-negative bacteria have a cell wall that is:
A) Thick with multiple layers of peptidoglycan
B) Thin with an outer membrane containing lipopolysaccharide (LPS)
C) Composed only of peptidoglycan
D) Lacking an outer membrane
Answer B: Thin with an outer membrane containing lipopolysaccharide (LPS)
Rationale: Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane containing LPS.
5. Which component of Gram-negative bacteria is an endotoxin?
A) Peptidoglycan
B) Lipopolysaccharide (LPS)
C) Teichoic acid
D) Capsule
Answer B: Lipopolysaccharide (LPS)
Rationale: Lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria acts as an endotoxin.
6. The plasma membrane of bacteria is composed primarily of:
A) Phospholipid bilayer with embedded proteins
B) Peptidoglycan
C) Lipopolysaccharide
D) Chitin
Answer A: Phospholipid bilayer with embedded proteins
Rationale: The bacterial plasma membrane is a phospholipid bilayer with embedded proteins, similar to
eukaryotic membranes.
7. Which bacterial structure is responsible for motility?
A) Pili
B) Flagella
C) Capsule
,D) Fimbriae
Answer B: Flagella
Rationale: Flagella are long, whip-like appendages responsible for bacterial motility.
8. Which bacterial structure is involved in attachment to surfaces and conjugation?
A) Pili (including sex pili)
B) Flagella
C) Capsule
D) Endospore
Answer A: Pili (including sex pili)
Rationale: Pili, including sex pili (F-pili), are involved in attachment and conjugation (DNA transfer).
9. The bacterial capsule is composed of:
A) Peptidoglycan
B) Polysaccharides or polypeptides
C) Lipopolysaccharide
D) Teichoic acid
Answer B: Polysaccharides or polypeptides
Rationale: Capsules are composed of polysaccharides or polypeptides and provide protection against
phagocytosis.
10. Which of the following is a function of the bacterial capsule?
A) Protection against phagocytosis
B) Motility
C) Protein synthesis
D) DNA replication
Answer A: Protection against phagocytosis
Rationale: The capsule protects bacteria from phagocytosis and contributes to virulence.
11. Endospores are produced by which genera of bacteria?
A) Bacillus and Clostridium
B) Staphylococcus and Streptococcus
, C) Escherichia and Salmonella
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D) Pseudomonas and Neisseria
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Answer A: Bacillus and Clostridium
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Rationale: Endospores are produced by Gram-positive bacteria in the genera Bacillus and Clostridium.
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12. Which of the following is a characteristic of endospores?
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A) Highly resistant to heat, radiation, and chemicals
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B) Easily killed by disinfectants
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C) Sensitive to heat
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D) Replicate rapidly
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Answer A: Highly resistant to heat, radiation, and chemicals
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Rationale: Endospores are highly resistant structures that can survive harsh environmental conditions.
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13. The term "pleomorphic" refers to bacteria that:
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A) Are rod-shaped
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B) Vary in shape and size
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C) Are spherical
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D) Form chains
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Answer B: Vary in shape and size
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Rationale: Pleomorphic bacteria vary in shape and size, lacking a fixed morphology.
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14. Bacterial ribosomes are composed of:
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A) 80S subunits
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B) 70S subunits (50S + 30S)
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C) 60S subunits
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D) 40S subunits
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Answer B: 70S subunits (50S + 30S)
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Rationale: Bacterial ribosomes are 70S, composed of 50S and 30S subunits, unlike eukaryotic 80S
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15. Which antibiotic targets the bacterial ribosome?
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A) Penicillin
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LEARNING | 250 QUESTIONS
Questions 1–250
#### SECTION 1: BACTERIAL CELL STRUCTURE & FUNCTION (Questions 1–50)
1. Which of the following is a distinguishing feature of prokaryotic cells compared to eukaryotic
cells?
A) Presence of a nucleus
B) Lack of membrane-bound organelles
C) Presence of mitochondria
D) Presence of endoplasmic reticulum
Answer B: Lack of membrane-bound organelles
Rationale: Prokaryotic cells lack membrane-bound organelles, including a nucleus, mitochondria, and
endoplasmic reticulum.
2. The bacterial cell wall is composed primarily of:
A) Chitin
B) Cellulose
C) Peptidoglycan
D) Lipopolysaccharide
Answer C: Peptidoglycan
Rationale: Bacterial cell walls contain peptidoglycan, a polymer of N-acetylglucosamine and N-
acetylmuramic acid.
3. Gram-positive bacteria have a cell wall that is:
A) Thick and composed of multiple layers of peptidoglycan
B) Thin with an outer membrane
C) Composed only of lipopolysaccharide
D) Lacking peptidoglycan
Answer A: Thick and composed of multiple layers of peptidoglycan
,Rationale: Gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet-iodine
complex.
4. Gram-negative bacteria have a cell wall that is:
A) Thick with multiple layers of peptidoglycan
B) Thin with an outer membrane containing lipopolysaccharide (LPS)
C) Composed only of peptidoglycan
D) Lacking an outer membrane
Answer B: Thin with an outer membrane containing lipopolysaccharide (LPS)
Rationale: Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane containing LPS.
5. Which component of Gram-negative bacteria is an endotoxin?
A) Peptidoglycan
B) Lipopolysaccharide (LPS)
C) Teichoic acid
D) Capsule
Answer B: Lipopolysaccharide (LPS)
Rationale: Lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria acts as an endotoxin.
6. The plasma membrane of bacteria is composed primarily of:
A) Phospholipid bilayer with embedded proteins
B) Peptidoglycan
C) Lipopolysaccharide
D) Chitin
Answer A: Phospholipid bilayer with embedded proteins
Rationale: The bacterial plasma membrane is a phospholipid bilayer with embedded proteins, similar to
eukaryotic membranes.
7. Which bacterial structure is responsible for motility?
A) Pili
B) Flagella
C) Capsule
,D) Fimbriae
Answer B: Flagella
Rationale: Flagella are long, whip-like appendages responsible for bacterial motility.
8. Which bacterial structure is involved in attachment to surfaces and conjugation?
A) Pili (including sex pili)
B) Flagella
C) Capsule
D) Endospore
Answer A: Pili (including sex pili)
Rationale: Pili, including sex pili (F-pili), are involved in attachment and conjugation (DNA transfer).
9. The bacterial capsule is composed of:
A) Peptidoglycan
B) Polysaccharides or polypeptides
C) Lipopolysaccharide
D) Teichoic acid
Answer B: Polysaccharides or polypeptides
Rationale: Capsules are composed of polysaccharides or polypeptides and provide protection against
phagocytosis.
10. Which of the following is a function of the bacterial capsule?
A) Protection against phagocytosis
B) Motility
C) Protein synthesis
D) DNA replication
Answer A: Protection against phagocytosis
Rationale: The capsule protects bacteria from phagocytosis and contributes to virulence.
11. Endospores are produced by which genera of bacteria?
A) Bacillus and Clostridium
B) Staphylococcus and Streptococcus
, C) Escherichia and Salmonella
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D) Pseudomonas and Neisseria
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Answer A: Bacillus and Clostridium
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Rationale: Endospores are produced by Gram-positive bacteria in the genera Bacillus and Clostridium.
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12. Which of the following is a characteristic of endospores?
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A) Highly resistant to heat, radiation, and chemicals
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B) Easily killed by disinfectants
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C) Sensitive to heat
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D) Replicate rapidly
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Answer A: Highly resistant to heat, radiation, and chemicals
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Rationale: Endospores are highly resistant structures that can survive harsh environmental conditions.
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13. The term "pleomorphic" refers to bacteria that:
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A) Are rod-shaped
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B) Vary in shape and size
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C) Are spherical
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D) Form chains
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Answer B: Vary in shape and size
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Rationale: Pleomorphic bacteria vary in shape and size, lacking a fixed morphology.
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14. Bacterial ribosomes are composed of:
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A) 80S subunits
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B) 70S subunits (50S + 30S)
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C) 60S subunits
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D) 40S subunits
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Answer B: 70S subunits (50S + 30S)
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Rationale: Bacterial ribosomes are 70S, composed of 50S and 30S subunits, unlike eukaryotic 80S
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15. Which antibiotic targets the bacterial ribosome?
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A) Penicillin
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