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 cells to a toxin
that selectively disrupts rough endoplasmic reticulum
function. Several hours later, the cells demonstrate
impaired export of membrane-bound proteins despite
preserved ATP production. The affected organelle most
directly explains which cellular process?
, A. Oxidative phosphorylation
B. Synthesis of secretory proteins
C. Digestion of intracellular debris
D. Packaging of lipids into lysosomes
Correct Answer: B
Rationale:
• Clinical Clue: Defective export of membrane-bound
proteins with preserved energy production localizes
dysfunction away from mitochondria.
• Mechanism: Rough endoplasmic reticulum (RER) contains
ribosome-studded membranes responsible for synthesis of
proteins destined for secretion, membranes, or lysosomes.
• Why the Correct Answer Is Right: Membrane-bound and
secretory proteins are synthesized on ribosomes attached
to the RER before modification and transport to the Golgi
apparatus.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation occurs in mitochondria.
o C: Intracellular digestion is mediated primarily by
lysosomes.
o D: Lipid packaging involves smooth ER and Golgi
processing rather than rough ER.
,• Exam Trap: Confusing rough ER with Golgi apparatus; the
Golgi modifies and packages proteins but does not
synthesize them.
• High-Yield Clinical Correlation: Plasma cells contain
abundant rough ER because of high immunoglobulin
production.
• Memory Anchor: “Rough ER = Ribosomes = Released
proteins.”
Q2. A child with recurrent bacterial infections is found to
have defective neutrophil chemotaxis caused by impaired
selectin-mediated rolling along vascular endothelium.
Which type of cell-to-cell interaction is primarily
disrupted?
A. Tight junction formation
B. Gap junction signaling
C. Transient cell adhesion
D. Desmosomal anchoring
Correct Answer: C
Rationale:
• Clinical Clue: Leukocyte rolling during inflammation
depends on weak, reversible interactions.
, • Mechanism: Selectins mediate transient adhesion
between leukocytes and endothelial cells, allowing rolling
before integrin activation.
• Why the Correct Answer Is Right: Transient adhesive
interactions are essential for leukocyte migration into
tissues during inflammation.
• Why the Other Options Are Wrong:
o A: Tight junctions create impermeable barriers
between epithelial cells.
o B: Gap junctions allow ion and small-molecule
communication.
o D: Desmosomes provide strong structural attachment
between cells.
• Exam Trap: Integrins mediate firm adhesion, whereas
selectins mediate rolling.
• High-Yield Clinical Correlation: Leukocyte adhesion
deficiency impairs neutrophil migration and causes
recurrent infections without pus formation.
• Memory Anchor: “Selectins slow cells down before
integrins lock them in.”
Q3. A pharmacologic agent blocks Na+/K+-ATPase activity
in cardiac myocytes. Which immediate intracellular change
would most likely occur?
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher exposes cultured human cells to a toxin
that selectively disrupts rough endoplasmic reticulum
function. Several hours later, the cells demonstrate
impaired export of membrane-bound proteins despite
preserved ATP production. The affected organelle most
directly explains which cellular process?
, A. Oxidative phosphorylation
B. Synthesis of secretory proteins
C. Digestion of intracellular debris
D. Packaging of lipids into lysosomes
Correct Answer: B
Rationale:
• Clinical Clue: Defective export of membrane-bound
proteins with preserved energy production localizes
dysfunction away from mitochondria.
• Mechanism: Rough endoplasmic reticulum (RER) contains
ribosome-studded membranes responsible for synthesis of
proteins destined for secretion, membranes, or lysosomes.
• Why the Correct Answer Is Right: Membrane-bound and
secretory proteins are synthesized on ribosomes attached
to the RER before modification and transport to the Golgi
apparatus.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation occurs in mitochondria.
o C: Intracellular digestion is mediated primarily by
lysosomes.
o D: Lipid packaging involves smooth ER and Golgi
processing rather than rough ER.
,• Exam Trap: Confusing rough ER with Golgi apparatus; the
Golgi modifies and packages proteins but does not
synthesize them.
• High-Yield Clinical Correlation: Plasma cells contain
abundant rough ER because of high immunoglobulin
production.
• Memory Anchor: “Rough ER = Ribosomes = Released
proteins.”
Q2. A child with recurrent bacterial infections is found to
have defective neutrophil chemotaxis caused by impaired
selectin-mediated rolling along vascular endothelium.
Which type of cell-to-cell interaction is primarily
disrupted?
A. Tight junction formation
B. Gap junction signaling
C. Transient cell adhesion
D. Desmosomal anchoring
Correct Answer: C
Rationale:
• Clinical Clue: Leukocyte rolling during inflammation
depends on weak, reversible interactions.
, • Mechanism: Selectins mediate transient adhesion
between leukocytes and endothelial cells, allowing rolling
before integrin activation.
• Why the Correct Answer Is Right: Transient adhesive
interactions are essential for leukocyte migration into
tissues during inflammation.
• Why the Other Options Are Wrong:
o A: Tight junctions create impermeable barriers
between epithelial cells.
o B: Gap junctions allow ion and small-molecule
communication.
o D: Desmosomes provide strong structural attachment
between cells.
• Exam Trap: Integrins mediate firm adhesion, whereas
selectins mediate rolling.
• High-Yield Clinical Correlation: Leukocyte adhesion
deficiency impairs neutrophil migration and causes
recurrent infections without pus formation.
• Memory Anchor: “Selectins slow cells down before
integrins lock them in.”
Q3. A pharmacologic agent blocks Na+/K+-ATPase activity
in cardiac myocytes. Which immediate intracellular change
would most likely occur?
