McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old child is diagnosed with recurrent severe
bacterial infections and poor wound healing. Genetic
analysis reveals impaired formation of tight junction
proteins in epithelial tissues. The child’s susceptibility to
infection is most directly explained by failure of which
physiologic function?
, A. ATP-dependent intracellular protein degradation
B. Maintenance of selective paracellular permeability
C. Mitochondrial oxidative phosphorylation
D. Ribosomal peptide-chain elongation
Correct Answer: B
Rationale:
• Clinical Clue: Recurrent infections with defective tight
junctions point to impaired epithelial barrier integrity.
• Mechanism: Tight junctions regulate paracellular transport
and prevent pathogen penetration between adjacent cells.
• Why the Correct Answer Is Right: Loss of selective
paracellular sealing permits microbial invasion and
disrupts tissue compartmentalization.
• Why the Other Options Are Wrong:
o A. Proteasomal degradation affects protein turnover,
not epithelial barrier defense.
o C. Oxidative phosphorylation defects cause energy
failure rather than selective permeability loss.
o D. Ribosomal dysfunction impairs protein synthesis
globally but does not specifically explain epithelial
leakage.
• Exam Trap: Confusing intercellular junction defects with
intracellular metabolic abnormalities.
,• High-Yield Clinical Correlation: Tight junction disruption
contributes to inflammatory bowel disease and blood-
brain barrier dysfunction.
• Memory Anchor: “Tight junctions tighten tissue borders.”
Q2. A researcher exposes cultured hepatocytes to cyanide,
resulting in rapid cessation of aerobic ATP production.
Which cellular process is expected to fail first?
A. Diffusion of oxygen across the plasma membrane
B. Sodium-potassium ATPase activity
C. Passive movement of water through aquaporins
D. Binding of steroid hormones to nuclear receptors
Correct Answer: B
Rationale:
• Clinical Clue: Cyanide blocks oxidative phosphorylation,
abruptly depleting ATP.
• Mechanism: The sodium-potassium pump requires
continuous ATP hydrolysis to maintain electrochemical
gradients.
• Why the Correct Answer Is Right: ATP depletion rapidly
disables active transport, causing cellular swelling and
membrane instability.
• Why the Other Options Are Wrong:
, o A. Oxygen diffusion is passive.
o C. Aquaporin-mediated water movement does not
directly require ATP.
o D. Steroid receptor binding depends on diffusion and
receptor affinity rather than immediate ATP
availability.
• Exam Trap: Assuming all membrane processes require
ATP.
• High-Yield Clinical Correlation: Early ischemic injury is
characterized by cellular swelling from Na+/K+ ATPase
failure.
• Memory Anchor: “No ATP, no ion gradient.”
Q3. A patient with chronic alcohol use develops
hepatocellular injury characterized by accumulation of
misfolded proteins within the cytoplasm. Which organelle
is most directly responsible for recognizing and packaging
these proteins for degradation?
A. Smooth endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Rough endoplasmic reticulum
Correct Answer: D
Rationale:
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old child is diagnosed with recurrent severe
bacterial infections and poor wound healing. Genetic
analysis reveals impaired formation of tight junction
proteins in epithelial tissues. The child’s susceptibility to
infection is most directly explained by failure of which
physiologic function?
, A. ATP-dependent intracellular protein degradation
B. Maintenance of selective paracellular permeability
C. Mitochondrial oxidative phosphorylation
D. Ribosomal peptide-chain elongation
Correct Answer: B
Rationale:
• Clinical Clue: Recurrent infections with defective tight
junctions point to impaired epithelial barrier integrity.
• Mechanism: Tight junctions regulate paracellular transport
and prevent pathogen penetration between adjacent cells.
• Why the Correct Answer Is Right: Loss of selective
paracellular sealing permits microbial invasion and
disrupts tissue compartmentalization.
• Why the Other Options Are Wrong:
o A. Proteasomal degradation affects protein turnover,
not epithelial barrier defense.
o C. Oxidative phosphorylation defects cause energy
failure rather than selective permeability loss.
o D. Ribosomal dysfunction impairs protein synthesis
globally but does not specifically explain epithelial
leakage.
• Exam Trap: Confusing intercellular junction defects with
intracellular metabolic abnormalities.
,• High-Yield Clinical Correlation: Tight junction disruption
contributes to inflammatory bowel disease and blood-
brain barrier dysfunction.
• Memory Anchor: “Tight junctions tighten tissue borders.”
Q2. A researcher exposes cultured hepatocytes to cyanide,
resulting in rapid cessation of aerobic ATP production.
Which cellular process is expected to fail first?
A. Diffusion of oxygen across the plasma membrane
B. Sodium-potassium ATPase activity
C. Passive movement of water through aquaporins
D. Binding of steroid hormones to nuclear receptors
Correct Answer: B
Rationale:
• Clinical Clue: Cyanide blocks oxidative phosphorylation,
abruptly depleting ATP.
• Mechanism: The sodium-potassium pump requires
continuous ATP hydrolysis to maintain electrochemical
gradients.
• Why the Correct Answer Is Right: ATP depletion rapidly
disables active transport, causing cellular swelling and
membrane instability.
• Why the Other Options Are Wrong:
, o A. Oxygen diffusion is passive.
o C. Aquaporin-mediated water movement does not
directly require ATP.
o D. Steroid receptor binding depends on diffusion and
receptor affinity rather than immediate ATP
availability.
• Exam Trap: Assuming all membrane processes require
ATP.
• High-Yield Clinical Correlation: Early ischemic injury is
characterized by cellular swelling from Na+/K+ ATPase
failure.
• Memory Anchor: “No ATP, no ion gradient.”
Q3. A patient with chronic alcohol use develops
hepatocellular injury characterized by accumulation of
misfolded proteins within the cytoplasm. Which organelle
is most directly responsible for recognizing and packaging
these proteins for degradation?
A. Smooth endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Rough endoplasmic reticulum
Correct Answer: D
Rationale:
