McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 42-year-old man develops progressive muscle
weakness after prolonged exposure to a toxin that
selectively impairs mitochondrial oxidative
phosphorylation. Despite adequate oxygen delivery,
, skeletal muscle cells demonstrate markedly reduced ATP
production and increased lactate accumulation. Which
cellular process is most directly impaired in this patient?
A. Anaerobic glycolysis within the cytosol
B. Electron transport–mediated ATP synthesis
C. Pentose phosphate pathway activation
D. Lysosomal degradation of glycogen
E. Cytoplasmic protein translation
Correct Answer: B
Rationale:
• Clinical Clue: Reduced ATP despite adequate oxygen and
elevated lactate indicates failure of aerobic metabolism.
• Mechanism: Oxidative phosphorylation occurs along the
inner mitochondrial membrane and depends on the
electron transport chain to generate ATP.
• Why the Correct Answer Is Right: Disruption of electron
transport prevents efficient ATP generation, forcing cells
toward anaerobic glycolysis and lactate production.
• Why the Other Options Are Wrong:
o A. Anaerobic glycolysis is increased, not impaired.
o C. The pentose phosphate pathway mainly generates
NADPH and ribose.
o D. Glycogen degradation occurs in lysosomes and
cytoplasm, unrelated to oxidative phosphorylation.
, o E. Protein translation requires ATP but is not the
primary defect.
• Exam Trap: Normal oxygenation does not exclude cellular
hypoxia when mitochondria cannot utilize oxygen.
• High-Yield Clinical Correlation: Cyanide poisoning similarly
blocks oxidative phosphorylation and causes lactic
acidosis.
• Memory Anchor: “Mitochondria use oxygen to make ATP.”
Q2. A researcher compares rapidly dividing bacterial cells
with human hepatocytes. She notes that the bacterial cells
lack membrane-bound organelles and contain circular DNA
localized within a nucleoid region. Which feature best
distinguishes the human hepatocyte from the bacterial
cell?
A. Ability to synthesize proteins
B. Presence of plasma membrane transport proteins
C. Ribosome-mediated translation
D. Membrane-bound nucleus containing linear
chromosomes
E. Dependence on ATP for metabolic reactions
Correct Answer: D
Rationale:
, • Clinical Clue: Comparison between prokaryotic and
eukaryotic organization.
• Mechanism: Eukaryotic cells possess membrane-bound
organelles including a nucleus containing linear DNA.
• Why the Correct Answer Is Right: The defining distinction
is compartmentalization with a true nucleus.
• Why the Other Options Are Wrong:
o A. Both cell types synthesize proteins.
o B. Both possess membrane transport proteins.
o C. Ribosomes exist in both.
o D. Correct because bacteria lack a membrane-bound
nucleus.
o E. ATP is universally required.
• Exam Trap: Ribosomes are present in both prokaryotes
and eukaryotes.
• High-Yield Clinical Correlation: Many antibiotics selectively
target bacterial ribosomes because they differ structurally
from eukaryotic ribosomes.
• Memory Anchor: “Prokaryotes lack compartments;
eukaryotes compartmentalize.”
Q3. A child with an inherited disorder develops severe
neurologic dysfunction due to defective lysosomal enzyme
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A 42-year-old man develops progressive muscle
weakness after prolonged exposure to a toxin that
selectively impairs mitochondrial oxidative
phosphorylation. Despite adequate oxygen delivery,
, skeletal muscle cells demonstrate markedly reduced ATP
production and increased lactate accumulation. Which
cellular process is most directly impaired in this patient?
A. Anaerobic glycolysis within the cytosol
B. Electron transport–mediated ATP synthesis
C. Pentose phosphate pathway activation
D. Lysosomal degradation of glycogen
E. Cytoplasmic protein translation
Correct Answer: B
Rationale:
• Clinical Clue: Reduced ATP despite adequate oxygen and
elevated lactate indicates failure of aerobic metabolism.
• Mechanism: Oxidative phosphorylation occurs along the
inner mitochondrial membrane and depends on the
electron transport chain to generate ATP.
• Why the Correct Answer Is Right: Disruption of electron
transport prevents efficient ATP generation, forcing cells
toward anaerobic glycolysis and lactate production.
• Why the Other Options Are Wrong:
o A. Anaerobic glycolysis is increased, not impaired.
o C. The pentose phosphate pathway mainly generates
NADPH and ribose.
o D. Glycogen degradation occurs in lysosomes and
cytoplasm, unrelated to oxidative phosphorylation.
, o E. Protein translation requires ATP but is not the
primary defect.
• Exam Trap: Normal oxygenation does not exclude cellular
hypoxia when mitochondria cannot utilize oxygen.
• High-Yield Clinical Correlation: Cyanide poisoning similarly
blocks oxidative phosphorylation and causes lactic
acidosis.
• Memory Anchor: “Mitochondria use oxygen to make ATP.”
Q2. A researcher compares rapidly dividing bacterial cells
with human hepatocytes. She notes that the bacterial cells
lack membrane-bound organelles and contain circular DNA
localized within a nucleoid region. Which feature best
distinguishes the human hepatocyte from the bacterial
cell?
A. Ability to synthesize proteins
B. Presence of plasma membrane transport proteins
C. Ribosome-mediated translation
D. Membrane-bound nucleus containing linear
chromosomes
E. Dependence on ATP for metabolic reactions
Correct Answer: D
Rationale:
, • Clinical Clue: Comparison between prokaryotic and
eukaryotic organization.
• Mechanism: Eukaryotic cells possess membrane-bound
organelles including a nucleus containing linear DNA.
• Why the Correct Answer Is Right: The defining distinction
is compartmentalization with a true nucleus.
• Why the Other Options Are Wrong:
o A. Both cell types synthesize proteins.
o B. Both possess membrane transport proteins.
o C. Ribosomes exist in both.
o D. Correct because bacteria lack a membrane-bound
nucleus.
o E. ATP is universally required.
• Exam Trap: Ribosomes are present in both prokaryotes
and eukaryotes.
• High-Yield Clinical Correlation: Many antibiotics selectively
target bacterial ribosomes because they differ structurally
from eukaryotic ribosomes.
• Memory Anchor: “Prokaryotes lack compartments;
eukaryotes compartmentalize.”
Q3. A child with an inherited disorder develops severe
neurologic dysfunction due to defective lysosomal enzyme
