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 boy develops recurrent bacterial infections
and delayed wound healing. Genetic analysis demonstrates a
mutation affecting actin filament organization within
leukocytes, resulting in impaired chemotaxis and phagocytosis.
Dysfunction of which cellular component most directly explains
these findings?
,A. Rough endoplasmic reticulum
B. Microtubules
C. Cytoskeleton microfilaments
D. Golgi apparatus
Correct Answer: C
Rationale:
• Clinical Clue: Recurrent infections with defective leukocyte
migration suggest impaired cellular motility.
• Mechanism: Actin-containing microfilaments are essential
for cell shape changes, migration, endocytosis, and
phagocytosis.
• Why the Correct Answer Is Right: Microfilaments enable
pseudopod formation and directional movement required
for immune cell function.
• Why the Other Options Are Wrong:
o A. Rough ER synthesizes proteins but does not
mediate motility.
o B. Microtubules participate in intracellular transport
and mitotic spindle formation more than chemotaxis.
o D. Golgi apparatus modifies and packages proteins.
• Exam Trap: Confusing microtubules with microfilaments
because both are cytoskeletal elements.
, • High-Yield Clinical Correlation: Defects in actin dynamics
contribute to immunodeficiency syndromes with impaired
neutrophil migration.
• Memory Anchor: “Actin allows action and movement.”
Q2. A researcher exposes cultured hepatocytes to cyanide,
leading to rapid ATP depletion despite adequate oxygen
availability. Which intracellular structure is most directly
inhibited?
A. Lysosome
B. Mitochondrion
C. Nucleolus
D. Peroxisome
Correct Answer: B
Rationale:
• Clinical Clue: Cyanide poisoning causes abrupt failure of
aerobic ATP production.
• Mechanism: Cyanide inhibits cytochrome oxidase in the
mitochondrial electron transport chain.
• Why the Correct Answer Is Right: Mitochondria generate
ATP through oxidative phosphorylation.
• Why the Other Options Are Wrong:
o A. Lysosomes digest cellular debris.
, o C. Nucleolus synthesizes ribosomal RNA.
o D. Peroxisomes perform oxidative reactions involving
fatty acids.
• Exam Trap: Assuming oxygen presence guarantees ATP
production.
• High-Yield Clinical Correlation: Histotoxic hypoxia occurs
when cells cannot utilize oxygen despite adequate
delivery.
• Memory Anchor: “Mitochondria make metabolic energy.”
Q3. A patient with chronic alcohol use develops hepatocellular
injury associated with accumulation of misfolded proteins
inside the cell. Dysfunction of which organelle best accounts for
this process?
A. Smooth endoplasmic reticulum
B. Ribosome
C. Rough endoplasmic reticulum
D. Centrosome
Correct Answer: C
Rationale:
• Clinical Clue: Protein accumulation suggests impaired
synthesis or folding.
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old boy develops recurrent bacterial infections
and delayed wound healing. Genetic analysis demonstrates a
mutation affecting actin filament organization within
leukocytes, resulting in impaired chemotaxis and phagocytosis.
Dysfunction of which cellular component most directly explains
these findings?
,A. Rough endoplasmic reticulum
B. Microtubules
C. Cytoskeleton microfilaments
D. Golgi apparatus
Correct Answer: C
Rationale:
• Clinical Clue: Recurrent infections with defective leukocyte
migration suggest impaired cellular motility.
• Mechanism: Actin-containing microfilaments are essential
for cell shape changes, migration, endocytosis, and
phagocytosis.
• Why the Correct Answer Is Right: Microfilaments enable
pseudopod formation and directional movement required
for immune cell function.
• Why the Other Options Are Wrong:
o A. Rough ER synthesizes proteins but does not
mediate motility.
o B. Microtubules participate in intracellular transport
and mitotic spindle formation more than chemotaxis.
o D. Golgi apparatus modifies and packages proteins.
• Exam Trap: Confusing microtubules with microfilaments
because both are cytoskeletal elements.
, • High-Yield Clinical Correlation: Defects in actin dynamics
contribute to immunodeficiency syndromes with impaired
neutrophil migration.
• Memory Anchor: “Actin allows action and movement.”
Q2. A researcher exposes cultured hepatocytes to cyanide,
leading to rapid ATP depletion despite adequate oxygen
availability. Which intracellular structure is most directly
inhibited?
A. Lysosome
B. Mitochondrion
C. Nucleolus
D. Peroxisome
Correct Answer: B
Rationale:
• Clinical Clue: Cyanide poisoning causes abrupt failure of
aerobic ATP production.
• Mechanism: Cyanide inhibits cytochrome oxidase in the
mitochondrial electron transport chain.
• Why the Correct Answer Is Right: Mitochondria generate
ATP through oxidative phosphorylation.
• Why the Other Options Are Wrong:
o A. Lysosomes digest cellular debris.
, o C. Nucleolus synthesizes ribosomal RNA.
o D. Peroxisomes perform oxidative reactions involving
fatty acids.
• Exam Trap: Assuming oxygen presence guarantees ATP
production.
• High-Yield Clinical Correlation: Histotoxic hypoxia occurs
when cells cannot utilize oxygen despite adequate
delivery.
• Memory Anchor: “Mitochondria make metabolic energy.”
Q3. A patient with chronic alcohol use develops hepatocellular
injury associated with accumulation of misfolded proteins
inside the cell. Dysfunction of which organelle best accounts for
this process?
A. Smooth endoplasmic reticulum
B. Ribosome
C. Rough endoplasmic reticulum
D. Centrosome
Correct Answer: C
Rationale:
• Clinical Clue: Protein accumulation suggests impaired
synthesis or folding.
