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 a mitochondrial
DNA disorder after progressive exercise intolerance, lactic
acidosis, and neuromuscular weakness. Muscle biopsy
, demonstrates ragged-red fibers. The patient’s symptoms
are most directly explained by failure of which cellular
process?
A. Ribosomal peptide synthesis
B. Oxidative phosphorylation
C. Golgi-mediated protein packaging
D. Lysosomal degradation of glycogen
Correct Answer: B
Rationale:
• Clinical Clue: Lactic acidosis with exercise intolerance
strongly suggests impaired aerobic ATP generation.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation via the electron transport chain.
• Why the Correct Answer Is Right: Defective oxidative
phosphorylation reduces ATP production and shifts
metabolism toward anaerobic glycolysis, increasing
lactate.
• Why the Other Options Are Wrong:
o A: Ribosomal dysfunction impairs protein synthesis
but does not primarily cause lactic acidosis.
o C: Golgi dysfunction alters protein trafficking rather
than aerobic metabolism.
o D: Lysosomal glycogen accumulation causes storage
diseases with different clinical patterns.
,• Exam Trap: Mitochondria possess their own DNA and
maternal inheritance pattern, which commonly appears in
vignette-based questions.
• High-Yield Clinical Correlation: High-energy tissues such as
skeletal muscle, myocardium, and neurons are most
vulnerable to mitochondrial dysfunction.
• Memory Anchor: “Mitochondria malfunction → low ATP →
lactate rises.”
Q2. A researcher exposes cultured epithelial cells to a
toxin that selectively disrupts microtubule polymerization.
Which cellular activity would be most immediately
impaired?
A. Passive diffusion of oxygen
B. Intracellular vesicle transport
C. ATP generation within mitochondria
D. DNA transcription in the nucleus
Correct Answer: B
Rationale:
• Clinical Clue: Microtubules function as intracellular
transport tracks.
• Mechanism: Vesicles move along microtubules through
motor proteins such as dynein and kinesin.
, • Why the Correct Answer Is Right: Secretory vesicle
movement and organelle trafficking depend heavily on
intact microtubules.
• Why the Other Options Are Wrong:
o A: Oxygen diffusion occurs independently of the
cytoskeleton.
o C: ATP synthesis occurs at the mitochondrial inner
membrane.
o D: Transcription depends on nuclear enzymes rather
than microtubule integrity.
• Exam Trap: Cytoskeletal elements have distinct
functions—microfilaments for contraction, intermediate
filaments for structural stability, microtubules for
transport and mitosis.
• High-Yield Clinical Correlation: Chemotherapeutic agents
such as vincristine target microtubules to inhibit mitosis.
• Memory Anchor: “Microtubules move materials.”
Q3. A hospitalized patient develops severe edema after
extensive thermal burns. The fluid shift into the interstitial
compartment is best accounted for by disruption of which
membrane function?
A. Active sodium extrusion
B. Maintenance of selective permeability
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 a mitochondrial
DNA disorder after progressive exercise intolerance, lactic
acidosis, and neuromuscular weakness. Muscle biopsy
, demonstrates ragged-red fibers. The patient’s symptoms
are most directly explained by failure of which cellular
process?
A. Ribosomal peptide synthesis
B. Oxidative phosphorylation
C. Golgi-mediated protein packaging
D. Lysosomal degradation of glycogen
Correct Answer: B
Rationale:
• Clinical Clue: Lactic acidosis with exercise intolerance
strongly suggests impaired aerobic ATP generation.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation via the electron transport chain.
• Why the Correct Answer Is Right: Defective oxidative
phosphorylation reduces ATP production and shifts
metabolism toward anaerobic glycolysis, increasing
lactate.
• Why the Other Options Are Wrong:
o A: Ribosomal dysfunction impairs protein synthesis
but does not primarily cause lactic acidosis.
o C: Golgi dysfunction alters protein trafficking rather
than aerobic metabolism.
o D: Lysosomal glycogen accumulation causes storage
diseases with different clinical patterns.
,• Exam Trap: Mitochondria possess their own DNA and
maternal inheritance pattern, which commonly appears in
vignette-based questions.
• High-Yield Clinical Correlation: High-energy tissues such as
skeletal muscle, myocardium, and neurons are most
vulnerable to mitochondrial dysfunction.
• Memory Anchor: “Mitochondria malfunction → low ATP →
lactate rises.”
Q2. A researcher exposes cultured epithelial cells to a
toxin that selectively disrupts microtubule polymerization.
Which cellular activity would be most immediately
impaired?
A. Passive diffusion of oxygen
B. Intracellular vesicle transport
C. ATP generation within mitochondria
D. DNA transcription in the nucleus
Correct Answer: B
Rationale:
• Clinical Clue: Microtubules function as intracellular
transport tracks.
• Mechanism: Vesicles move along microtubules through
motor proteins such as dynein and kinesin.
, • Why the Correct Answer Is Right: Secretory vesicle
movement and organelle trafficking depend heavily on
intact microtubules.
• Why the Other Options Are Wrong:
o A: Oxygen diffusion occurs independently of the
cytoskeleton.
o C: ATP synthesis occurs at the mitochondrial inner
membrane.
o D: Transcription depends on nuclear enzymes rather
than microtubule integrity.
• Exam Trap: Cytoskeletal elements have distinct
functions—microfilaments for contraction, intermediate
filaments for structural stability, microtubules for
transport and mitosis.
• High-Yield Clinical Correlation: Chemotherapeutic agents
such as vincristine target microtubules to inhibit mitosis.
• Memory Anchor: “Microtubules move materials.”
Q3. A hospitalized patient develops severe edema after
extensive thermal burns. The fluid shift into the interstitial
compartment is best accounted for by disruption of which
membrane function?
A. Active sodium extrusion
B. Maintenance of selective permeability
