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 presents with recurrent pyogenic
infections and poor wound healing. Genetic testing identifies a
defect in actin polymerization within leukocytes, impairing
pseudopod formation. The dysfunctional cellular component
most directly affects which process?
A. Oxidative phosphorylation within mitochondria
B. Intracellular protein synthesis on ribosomes
,C. Vesicular trafficking through the Golgi apparatus
D. Cellular motility and membrane deformation
E. DNA transcription within the nucleus
Correct Answer: D
Rationale:
• Clinical Clue: Recurrent infections with impaired leukocyte
movement suggests defective cytoskeletal dynamics.
• Mechanism: Actin microfilaments are critical for cell
movement, shape change, endocytosis, and phagocytosis.
• Why the Correct Answer Is Right: Actin polymerization
enables pseudopod extension and membrane deformation
necessary for leukocyte migration and phagocytosis.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation depends on
mitochondrial enzymes, not actin.
o B: Ribosomes mediate translation independently of
cytoskeletal motility.
o C: Golgi trafficking primarily depends on microtubules
and vesicle proteins.
o E: Nuclear transcription is unrelated to actin-
mediated motility defects.
• Exam Trap: Cytoskeletal questions often tempt confusion
between microfilaments and microtubules.
, • High-Yield Clinical Correlation: Leukocyte adhesion and
migration disorders commonly involve cytoskeletal
abnormalities.
• Memory Anchor: “Actin allows action”—movement and
shape change.
Q2. A researcher exposes cultured hepatocytes to cyanide,
resulting in rapid ATP depletion despite adequate oxygen
delivery. Which cellular structure is primarily inhibited?
A. Lysosome
B. Smooth endoplasmic reticulum
C. Mitochondrion
D. Peroxisome
E. Nucleolus
Correct Answer: C
Rationale:
• Clinical Clue: Cyanide poisoning classically causes
histotoxic hypoxia with failure of ATP production.
• Mechanism: Cyanide inhibits cytochrome oxidase in the
electron transport chain.
• Why the Correct Answer Is Right: Mitochondria generate
ATP through oxidative phosphorylation; cyanide blocks
aerobic respiration.
• Why the Other Options Are Wrong:
, o A: Lysosomes digest cellular debris.
o B: Smooth ER handles lipid synthesis and
detoxification.
o D: Peroxisomes metabolize very-long-chain fatty acids
and hydrogen peroxide.
o E: The nucleolus synthesizes rRNA.
• Exam Trap: Oxygen may be present, but cells cannot utilize
it due to mitochondrial blockade.
• High-Yield Clinical Correlation: Severe lactic acidosis
develops because cells shift to anaerobic metabolism.
• Memory Anchor: Cyanide “chokes” the mitochondrial
electron transport chain.
Q3. A patient with chronic alcohol use develops hepatomegaly
and elevated liver enzymes. Hepatocyte biopsy demonstrates
marked proliferation of smooth endoplasmic reticulum. This
adaptation most directly reflects increased capacity for:
A. Protein glycosylation
B. Detoxification reactions
C. Ribosomal assembly
D. DNA replication
E. Lysosomal digestion
Correct Answer: B
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 6-year-old boy presents with recurrent pyogenic
infections and poor wound healing. Genetic testing identifies a
defect in actin polymerization within leukocytes, impairing
pseudopod formation. The dysfunctional cellular component
most directly affects which process?
A. Oxidative phosphorylation within mitochondria
B. Intracellular protein synthesis on ribosomes
,C. Vesicular trafficking through the Golgi apparatus
D. Cellular motility and membrane deformation
E. DNA transcription within the nucleus
Correct Answer: D
Rationale:
• Clinical Clue: Recurrent infections with impaired leukocyte
movement suggests defective cytoskeletal dynamics.
• Mechanism: Actin microfilaments are critical for cell
movement, shape change, endocytosis, and phagocytosis.
• Why the Correct Answer Is Right: Actin polymerization
enables pseudopod extension and membrane deformation
necessary for leukocyte migration and phagocytosis.
• Why the Other Options Are Wrong:
o A: Oxidative phosphorylation depends on
mitochondrial enzymes, not actin.
o B: Ribosomes mediate translation independently of
cytoskeletal motility.
o C: Golgi trafficking primarily depends on microtubules
and vesicle proteins.
o E: Nuclear transcription is unrelated to actin-
mediated motility defects.
• Exam Trap: Cytoskeletal questions often tempt confusion
between microfilaments and microtubules.
, • High-Yield Clinical Correlation: Leukocyte adhesion and
migration disorders commonly involve cytoskeletal
abnormalities.
• Memory Anchor: “Actin allows action”—movement and
shape change.
Q2. A researcher exposes cultured hepatocytes to cyanide,
resulting in rapid ATP depletion despite adequate oxygen
delivery. Which cellular structure is primarily inhibited?
A. Lysosome
B. Smooth endoplasmic reticulum
C. Mitochondrion
D. Peroxisome
E. Nucleolus
Correct Answer: C
Rationale:
• Clinical Clue: Cyanide poisoning classically causes
histotoxic hypoxia with failure of ATP production.
• Mechanism: Cyanide inhibits cytochrome oxidase in the
electron transport chain.
• Why the Correct Answer Is Right: Mitochondria generate
ATP through oxidative phosphorylation; cyanide blocks
aerobic respiration.
• Why the Other Options Are Wrong:
, o A: Lysosomes digest cellular debris.
o B: Smooth ER handles lipid synthesis and
detoxification.
o D: Peroxisomes metabolize very-long-chain fatty acids
and hydrogen peroxide.
o E: The nucleolus synthesizes rRNA.
• Exam Trap: Oxygen may be present, but cells cannot utilize
it due to mitochondrial blockade.
• High-Yield Clinical Correlation: Severe lactic acidosis
develops because cells shift to anaerobic metabolism.
• Memory Anchor: Cyanide “chokes” the mitochondrial
electron transport chain.
Q3. A patient with chronic alcohol use develops hepatomegaly
and elevated liver enzymes. Hepatocyte biopsy demonstrates
marked proliferation of smooth endoplasmic reticulum. This
adaptation most directly reflects increased capacity for:
A. Protein glycosylation
B. Detoxification reactions
C. Ribosomal assembly
D. DNA replication
E. Lysosomal digestion
Correct Answer: B
