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 human hepatocytes to a
toxin that selectively disrupts rough endoplasmic reticulum
function. Within hours, the cells demonstrate impaired plasma
protein synthesis and intracellular accumulation of incomplete
peptide chains. This finding most directly reflects failure of
which cellular process?
,A. Oxidative phosphorylation
B. Post-translational protein synthesis and processing
C. Lysosomal degradation of membrane proteins
D. β-oxidation of fatty acids
Correct Answer: B
Rationale:
• Clinical Clue: Impaired plasma protein synthesis with
accumulation of incomplete peptides points to rough
endoplasmic reticulum dysfunction.
• Mechanism: Ribosomes attached to rough ER synthesize
proteins destined for secretion or membrane
incorporation.
• Why the Correct Answer Is Right: Hepatocytes depend
heavily on rough ER for synthesis and initial modification
of plasma proteins such as albumin and clotting factors.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation occurs primarily in
mitochondria.
o C: Lysosomes degrade intracellular debris rather than
synthesize proteins.
o D: β-oxidation occurs in mitochondria and
peroxisomes.
• Exam Trap: Confusing rough ER with Golgi apparatus; Golgi
modifies and packages proteins after ER synthesis.
, • High-Yield Clinical Correlation: Plasma cells and
hepatocytes are especially rich in rough ER because of high
secretory activity.
• Memory Anchor: “Rough ER = ribosome-rich protein
factory.”
Q2. A child with recurrent respiratory infections is found to
have defective ciliary motility due to abnormal dynein arms.
The underlying defect most directly involves dysfunction of
which cellular structure?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Desmosomes
Correct Answer: B
Rationale:
• Clinical Clue: Impaired ciliary movement strongly suggests
a microtubule-associated defect.
• Mechanism: Cilia contain microtubules arranged in a 9+2
structure powered by dynein ATPase activity.
• Why the Correct Answer Is Right: Dynein arms generate
sliding motion between microtubules, enabling
coordinated ciliary beating.
• Why the Other Options Are Wrong:
, o A: Intermediate filaments provide structural support.
o C: Microfilaments mainly mediate contraction and
shape changes.
o D: Desmosomes are adhesion junctions between
cells.
• Exam Trap: Confusing microtubules with actin
microfilaments because both contribute to cellular
movement.
• High-Yield Clinical Correlation: Primary ciliary dyskinesia
can produce chronic sinusitis, bronchiectasis, and
infertility.
• Memory Anchor: “Cilia glide on microtubule tracks.”
Q3. A patient develops profound skeletal muscle fatigue after
exposure to cyanide. Despite adequate oxygen delivery, ATP
production rapidly declines. The toxin most likely inhibits which
process?
A. Glycolysis in the cytoplasm
B. Electron transport within mitochondria
C. Ribosomal peptide elongation
D. Lysosomal hydrolysis
Correct Answer: B
Rationale:
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher exposes cultured human hepatocytes to a
toxin that selectively disrupts rough endoplasmic reticulum
function. Within hours, the cells demonstrate impaired plasma
protein synthesis and intracellular accumulation of incomplete
peptide chains. This finding most directly reflects failure of
which cellular process?
,A. Oxidative phosphorylation
B. Post-translational protein synthesis and processing
C. Lysosomal degradation of membrane proteins
D. β-oxidation of fatty acids
Correct Answer: B
Rationale:
• Clinical Clue: Impaired plasma protein synthesis with
accumulation of incomplete peptides points to rough
endoplasmic reticulum dysfunction.
• Mechanism: Ribosomes attached to rough ER synthesize
proteins destined for secretion or membrane
incorporation.
• Why the Correct Answer Is Right: Hepatocytes depend
heavily on rough ER for synthesis and initial modification
of plasma proteins such as albumin and clotting factors.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation occurs primarily in
mitochondria.
o C: Lysosomes degrade intracellular debris rather than
synthesize proteins.
o D: β-oxidation occurs in mitochondria and
peroxisomes.
• Exam Trap: Confusing rough ER with Golgi apparatus; Golgi
modifies and packages proteins after ER synthesis.
, • High-Yield Clinical Correlation: Plasma cells and
hepatocytes are especially rich in rough ER because of high
secretory activity.
• Memory Anchor: “Rough ER = ribosome-rich protein
factory.”
Q2. A child with recurrent respiratory infections is found to
have defective ciliary motility due to abnormal dynein arms.
The underlying defect most directly involves dysfunction of
which cellular structure?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Desmosomes
Correct Answer: B
Rationale:
• Clinical Clue: Impaired ciliary movement strongly suggests
a microtubule-associated defect.
• Mechanism: Cilia contain microtubules arranged in a 9+2
structure powered by dynein ATPase activity.
• Why the Correct Answer Is Right: Dynein arms generate
sliding motion between microtubules, enabling
coordinated ciliary beating.
• Why the Other Options Are Wrong:
, o A: Intermediate filaments provide structural support.
o C: Microfilaments mainly mediate contraction and
shape changes.
o D: Desmosomes are adhesion junctions between
cells.
• Exam Trap: Confusing microtubules with actin
microfilaments because both contribute to cellular
movement.
• High-Yield Clinical Correlation: Primary ciliary dyskinesia
can produce chronic sinusitis, bronchiectasis, and
infertility.
• Memory Anchor: “Cilia glide on microtubule tracks.”
Q3. A patient develops profound skeletal muscle fatigue after
exposure to cyanide. Despite adequate oxygen delivery, ATP
production rapidly declines. The toxin most likely inhibits which
process?
A. Glycolysis in the cytoplasm
B. Electron transport within mitochondria
C. Ribosomal peptide elongation
D. Lysosomal hydrolysis
Correct Answer: B
Rationale:
