McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher studying epithelial barrier integrity
observes that intestinal cells exposed to a bacterial toxin
lose selective permeability between adjacent cells,
allowing paracellular leakage of ions and water. Disruption
, of which cellular structure most directly explains this
finding?
A. Desmosomes
B. Tight junctions
C. Gap junctions
D. Hemidesmosomes
Correct Answer: B
Rationale:
• Clinical Clue: “Paracellular leakage” indicates loss of the
seal between adjacent epithelial cells.
• Mechanism: Tight junctions form occluding barriers that
regulate movement between cells and maintain polarity.
• Why the Correct Answer Is Right: Tight junction disruption
increases permeability between epithelial cells, permitting
uncontrolled diffusion of solutes and water.
• Why the Other Options Are Wrong:
o A. Desmosomes provide mechanical strength, not
permeability control.
o C. Gap junctions allow intercellular communication
via ion channels.
o D. Hemidesmosomes anchor cells to the basement
membrane.
,• Exam Trap: Confusing desmosomes with tight junctions
because both involve cell adhesion.
• High-Yield Clinical Correlation: Cholera toxin–related
diarrhea partly reflects altered epithelial transport and
junctional dysfunction.
• Memory Anchor: Tight junctions “tighten” the intercellular
seal.
Q2. A 6-year-old child develops severe fatigue and lactic
acidosis during a viral illness. Muscle biopsy demonstrates
structurally abnormal mitochondria with impaired
oxidative phosphorylation. Which cellular process is most
directly impaired?
A. Glycolysis in the cytosol
B. ATP generation through the electron transport chain
C. Protein synthesis on ribosomes
D. Lipid synthesis within smooth endoplasmic reticulum
Correct Answer: B
Rationale:
• Clinical Clue: Lactic acidosis and mitochondrial
abnormalities suggest defective aerobic ATP production.
• Mechanism: Oxidative phosphorylation occurs within the
inner mitochondrial membrane via the electron transport
chain.
, • Why the Correct Answer Is Right: Impaired mitochondrial
respiration reduces ATP generation and shifts metabolism
toward anaerobic glycolysis.
• Why the Other Options Are Wrong:
o A. Glycolysis occurs independently of mitochondria.
o C. Ribosomes synthesize proteins rather than ATP.
o D. Smooth ER primarily handles lipid metabolism and
detoxification.
• Exam Trap: Assuming glycolysis is the primary ATP source
in all tissues.
• High-Yield Clinical Correlation: Mitochondrial diseases
commonly affect high-energy tissues such as brain and
muscle.
• Memory Anchor: Mitochondria are the cell’s “power
plants.”
Q3. A patient with severe liver disease develops
accumulation of misfolded proteins within hepatocytes.
Cellular injury is exacerbated when intracellular proteins
fail to undergo degradation after ubiquitin tagging.
Dysfunction of which organelle best accounts for this
abnormality?
A. Golgi apparatus
B. Lysosome
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher studying epithelial barrier integrity
observes that intestinal cells exposed to a bacterial toxin
lose selective permeability between adjacent cells,
allowing paracellular leakage of ions and water. Disruption
, of which cellular structure most directly explains this
finding?
A. Desmosomes
B. Tight junctions
C. Gap junctions
D. Hemidesmosomes
Correct Answer: B
Rationale:
• Clinical Clue: “Paracellular leakage” indicates loss of the
seal between adjacent epithelial cells.
• Mechanism: Tight junctions form occluding barriers that
regulate movement between cells and maintain polarity.
• Why the Correct Answer Is Right: Tight junction disruption
increases permeability between epithelial cells, permitting
uncontrolled diffusion of solutes and water.
• Why the Other Options Are Wrong:
o A. Desmosomes provide mechanical strength, not
permeability control.
o C. Gap junctions allow intercellular communication
via ion channels.
o D. Hemidesmosomes anchor cells to the basement
membrane.
,• Exam Trap: Confusing desmosomes with tight junctions
because both involve cell adhesion.
• High-Yield Clinical Correlation: Cholera toxin–related
diarrhea partly reflects altered epithelial transport and
junctional dysfunction.
• Memory Anchor: Tight junctions “tighten” the intercellular
seal.
Q2. A 6-year-old child develops severe fatigue and lactic
acidosis during a viral illness. Muscle biopsy demonstrates
structurally abnormal mitochondria with impaired
oxidative phosphorylation. Which cellular process is most
directly impaired?
A. Glycolysis in the cytosol
B. ATP generation through the electron transport chain
C. Protein synthesis on ribosomes
D. Lipid synthesis within smooth endoplasmic reticulum
Correct Answer: B
Rationale:
• Clinical Clue: Lactic acidosis and mitochondrial
abnormalities suggest defective aerobic ATP production.
• Mechanism: Oxidative phosphorylation occurs within the
inner mitochondrial membrane via the electron transport
chain.
, • Why the Correct Answer Is Right: Impaired mitochondrial
respiration reduces ATP generation and shifts metabolism
toward anaerobic glycolysis.
• Why the Other Options Are Wrong:
o A. Glycolysis occurs independently of mitochondria.
o C. Ribosomes synthesize proteins rather than ATP.
o D. Smooth ER primarily handles lipid metabolism and
detoxification.
• Exam Trap: Assuming glycolysis is the primary ATP source
in all tissues.
• High-Yield Clinical Correlation: Mitochondrial diseases
commonly affect high-energy tissues such as brain and
muscle.
• Memory Anchor: Mitochondria are the cell’s “power
plants.”
Q3. A patient with severe liver disease develops
accumulation of misfolded proteins within hepatocytes.
Cellular injury is exacerbated when intracellular proteins
fail to undergo degradation after ubiquitin tagging.
Dysfunction of which organelle best accounts for this
abnormality?
A. Golgi apparatus
B. Lysosome
