Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and easy bruising. Genetic
testing reveals a mutation affecting integrin-mediated
attachment between leukocytes and vascular endothelium. The
defective process most directly impairs which cellular function?
A. ATP generation through oxidative phosphorylation
B. Cell-to-cell adhesion required for leukocyte migration
C. Ribosomal assembly of structural proteins
D. DNA repair during the S phase of the cell cycle
E. Endocytosis of extracellular pathogens
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent infections with impaired leukocyte migration
suggests defective adhesion molecule function.
Mechanism:
Integrins mediate firm adhesion of leukocytes to endothelial
surfaces before transmigration into tissues.
Why the Correct Answer Is Right:
Defective integrin function disrupts cell-to-cell adhesion and
prevents effective leukocyte extravasation during
inflammation.
Why the Other Options Are Wrong:
A. ATP production defects produce myopathic or neurologic
symptoms rather than isolated migration defects.
C. Ribosomal dysfunction affects protein synthesis globally.
D. DNA repair defects predispose to malignancy rather than
impaired leukocyte adhesion.
E. Phagocytosis may remain intact if leukocytes cannot reach
tissues.
Exam Trap (common misconception tested):
Confusing leukocyte adhesion defects with phagocytic killing
disorders.
High-Yield Clinical Correlation:
Cell adhesion molecules are essential for immune surveillance
and inflammatory recruitment.
,Q2. A researcher exposes hepatocytes to a toxin that uncouples
oxidative phosphorylation while preserving electron transport
activity. Which intracellular change is most likely to occur first?
A. Increased ATP synthesis
B. Accumulation of cytosolic glycogen
C. Decreased mitochondrial membrane proton gradient
D. Enhanced ribosomal translation
E. Arrest of cells in metaphase
Correct Answer: C
Rationale:
Clinical Clue:
Uncoupling oxidative phosphorylation disrupts ATP production
despite ongoing electron transport.
Mechanism:
The proton gradient across the inner mitochondrial membrane
drives ATP synthase activity.
Why the Correct Answer Is Right:
Uncoupling dissipates the proton gradient, preventing ATP
generation despite continued electron flow.
Why the Other Options Are Wrong:
A. ATP synthesis decreases.
B. Glycogen depletion rather than accumulation occurs during
energy failure.
, C. Correct.
D. Protein synthesis declines during ATP depletion.
E. Cell-cycle arrest is a downstream effect, not the earliest
event.
Exam Trap (common misconception tested):
Assuming electron transport automatically produces ATP.
High-Yield Clinical Correlation:
Mitochondrial dysfunction contributes to ischemic injury, toxin
exposure, and metabolic disease.
Q3. A patient with chronic alcohol use develops severe muscle
weakness. Muscle biopsy demonstrates swollen mitochondria
with disrupted cristae. The patient’s symptoms are best
explained by impaired production of which molecule?
A. Lactate
B. ATP
C. DNA polymerase
D. Cholesterol
E. Lysosomal hydrolases
Correct Answer: B
Rationale:
Clinical Clue:
Cristae disruption indicates mitochondrial injury.
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 6-year-old boy presents with recurrent bacterial
infections, delayed wound healing, and easy bruising. Genetic
testing reveals a mutation affecting integrin-mediated
attachment between leukocytes and vascular endothelium. The
defective process most directly impairs which cellular function?
A. ATP generation through oxidative phosphorylation
B. Cell-to-cell adhesion required for leukocyte migration
C. Ribosomal assembly of structural proteins
D. DNA repair during the S phase of the cell cycle
E. Endocytosis of extracellular pathogens
Correct Answer: B
,Rationale:
Clinical Clue:
Recurrent infections with impaired leukocyte migration
suggests defective adhesion molecule function.
Mechanism:
Integrins mediate firm adhesion of leukocytes to endothelial
surfaces before transmigration into tissues.
Why the Correct Answer Is Right:
Defective integrin function disrupts cell-to-cell adhesion and
prevents effective leukocyte extravasation during
inflammation.
Why the Other Options Are Wrong:
A. ATP production defects produce myopathic or neurologic
symptoms rather than isolated migration defects.
C. Ribosomal dysfunction affects protein synthesis globally.
D. DNA repair defects predispose to malignancy rather than
impaired leukocyte adhesion.
E. Phagocytosis may remain intact if leukocytes cannot reach
tissues.
Exam Trap (common misconception tested):
Confusing leukocyte adhesion defects with phagocytic killing
disorders.
High-Yield Clinical Correlation:
Cell adhesion molecules are essential for immune surveillance
and inflammatory recruitment.
,Q2. A researcher exposes hepatocytes to a toxin that uncouples
oxidative phosphorylation while preserving electron transport
activity. Which intracellular change is most likely to occur first?
A. Increased ATP synthesis
B. Accumulation of cytosolic glycogen
C. Decreased mitochondrial membrane proton gradient
D. Enhanced ribosomal translation
E. Arrest of cells in metaphase
Correct Answer: C
Rationale:
Clinical Clue:
Uncoupling oxidative phosphorylation disrupts ATP production
despite ongoing electron transport.
Mechanism:
The proton gradient across the inner mitochondrial membrane
drives ATP synthase activity.
Why the Correct Answer Is Right:
Uncoupling dissipates the proton gradient, preventing ATP
generation despite continued electron flow.
Why the Other Options Are Wrong:
A. ATP synthesis decreases.
B. Glycogen depletion rather than accumulation occurs during
energy failure.
, C. Correct.
D. Protein synthesis declines during ATP depletion.
E. Cell-cycle arrest is a downstream effect, not the earliest
event.
Exam Trap (common misconception tested):
Assuming electron transport automatically produces ATP.
High-Yield Clinical Correlation:
Mitochondrial dysfunction contributes to ischemic injury, toxin
exposure, and metabolic disease.
Q3. A patient with chronic alcohol use develops severe muscle
weakness. Muscle biopsy demonstrates swollen mitochondria
with disrupted cristae. The patient’s symptoms are best
explained by impaired production of which molecule?
A. Lactate
B. ATP
C. DNA polymerase
D. Cholesterol
E. Lysosomal hydrolases
Correct Answer: B
Rationale:
Clinical Clue:
Cristae disruption indicates mitochondrial injury.
