McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher exposes cultured hepatocytes to a toxin that
selectively disrupts rough endoplasmic reticulum function.
Several hours later, the cells demonstrate impaired plasma
protein synthesis and intracellular accumulation of unfolded
proteins. The observed findings are most directly explained by
failure of which cellular process?
,A. Oxidative phosphorylation
B. Post-translational protein processing
C. DNA replication
D. Lysosomal autophagy
Correct Answer: B
Rationale:
• Clinical Clue: Rough endoplasmic reticulum dysfunction
with impaired protein synthesis and unfolded protein
accumulation.
• Mechanism: The rough ER is responsible for synthesis,
folding, and initial modification of secretory and
membrane proteins.
• Why the Correct Answer Is Right: Plasma proteins
synthesized by hepatocytes require rough ER processing
before transport to the Golgi apparatus.
• Why the Other Options Are Wrong:
o A. Oxidative phosphorylation occurs in mitochondria.
o C. DNA replication occurs in the nucleus during S
phase.
o D. Autophagy primarily involves lysosomal
degradation pathways.
• Exam Trap: Confusing rough ER dysfunction with Golgi
pathology; the initial defect is protein synthesis and
folding.
, • High-Yield Clinical Correlation: ER stress contributes to
neurodegenerative disorders and metabolic diseases
through accumulation of misfolded proteins.
• Memory Anchor: “Rough ER = ribosome-driven protein
factory.”
Q2. A patient with an inherited mitochondrial disorder
develops severe exercise intolerance and lactic acidosis during
minimal exertion. Skeletal muscle biopsy reveals structurally
abnormal mitochondria. Which alteration best accounts for this
patient’s symptoms?
A. Failure of anaerobic glycolysis
B. Defective ATP generation through electron transport
C. Impaired lysosomal enzyme activation
D. Excessive nuclear transcription
Correct Answer: B
Rationale:
• Clinical Clue: Exercise intolerance and lactic acidosis
strongly suggest impaired aerobic metabolism.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation via the electron transport chain.
• Why the Correct Answer Is Right: Dysfunctional electron
transport decreases ATP production, forcing reliance on
anaerobic glycolysis and lactate accumulation.
, • Why the Other Options Are Wrong:
o A. Anaerobic glycolysis is increased, not absent.
o C. Lysosomes are unrelated to ATP production.
o D. Nuclear transcription does not explain lactic
acidosis.
• Exam Trap: Assuming glycolysis failure causes lactate
accumulation; lactate rises because glycolysis
compensates for mitochondrial dysfunction.
• High-Yield Clinical Correlation: Mitochondrial diseases
commonly affect high-energy tissues such as muscle,
brain, and myocardium.
• Memory Anchor: “Mitochondria power the cell; when
power fails, lactate rises.”
Q3. A pathologist examines epithelial tissue from a patient with
blistering skin disease and notes separation of adjacent
keratinocytes despite intact basement membranes. Dysfunction
of which structure most likely underlies this finding?
A. Tight junctions
B. Desmosomes
C. Gap junctions
D. Hemidesmosomes
Correct Answer: B
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher exposes cultured hepatocytes to a toxin that
selectively disrupts rough endoplasmic reticulum function.
Several hours later, the cells demonstrate impaired plasma
protein synthesis and intracellular accumulation of unfolded
proteins. The observed findings are most directly explained by
failure of which cellular process?
,A. Oxidative phosphorylation
B. Post-translational protein processing
C. DNA replication
D. Lysosomal autophagy
Correct Answer: B
Rationale:
• Clinical Clue: Rough endoplasmic reticulum dysfunction
with impaired protein synthesis and unfolded protein
accumulation.
• Mechanism: The rough ER is responsible for synthesis,
folding, and initial modification of secretory and
membrane proteins.
• Why the Correct Answer Is Right: Plasma proteins
synthesized by hepatocytes require rough ER processing
before transport to the Golgi apparatus.
• Why the Other Options Are Wrong:
o A. Oxidative phosphorylation occurs in mitochondria.
o C. DNA replication occurs in the nucleus during S
phase.
o D. Autophagy primarily involves lysosomal
degradation pathways.
• Exam Trap: Confusing rough ER dysfunction with Golgi
pathology; the initial defect is protein synthesis and
folding.
, • High-Yield Clinical Correlation: ER stress contributes to
neurodegenerative disorders and metabolic diseases
through accumulation of misfolded proteins.
• Memory Anchor: “Rough ER = ribosome-driven protein
factory.”
Q2. A patient with an inherited mitochondrial disorder
develops severe exercise intolerance and lactic acidosis during
minimal exertion. Skeletal muscle biopsy reveals structurally
abnormal mitochondria. Which alteration best accounts for this
patient’s symptoms?
A. Failure of anaerobic glycolysis
B. Defective ATP generation through electron transport
C. Impaired lysosomal enzyme activation
D. Excessive nuclear transcription
Correct Answer: B
Rationale:
• Clinical Clue: Exercise intolerance and lactic acidosis
strongly suggest impaired aerobic metabolism.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation via the electron transport chain.
• Why the Correct Answer Is Right: Dysfunctional electron
transport decreases ATP production, forcing reliance on
anaerobic glycolysis and lactate accumulation.
, • Why the Other Options Are Wrong:
o A. Anaerobic glycolysis is increased, not absent.
o C. Lysosomes are unrelated to ATP production.
o D. Nuclear transcription does not explain lactic
acidosis.
• Exam Trap: Assuming glycolysis failure causes lactate
accumulation; lactate rises because glycolysis
compensates for mitochondrial dysfunction.
• High-Yield Clinical Correlation: Mitochondrial diseases
commonly affect high-energy tissues such as muscle,
brain, and myocardium.
• Memory Anchor: “Mitochondria power the cell; when
power fails, lactate rises.”
Q3. A pathologist examines epithelial tissue from a patient with
blistering skin disease and notes separation of adjacent
keratinocytes despite intact basement membranes. Dysfunction
of which structure most likely underlies this finding?
A. Tight junctions
B. Desmosomes
C. Gap junctions
D. Hemidesmosomes
Correct Answer: B
