Understanding Pathophysiology
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 56-year-old man with chronic alcohol use disorder is
admitted with confusion, ataxia, and ophthalmoplegia.
Laboratory studies reveal elevated pyruvate and lactate levels.
Neuronal injury in this patient is most directly related to failure
of which cellular process?
A. Ribosomal peptide synthesis
B. Mitochondrial oxidative phosphorylation
C. Lysosomal protein degradation
D. Peroxisomal β-oxidation
E. Golgi-mediated protein packaging
Correct Answer: B
,Rationale:
Clinical Clue:
Neurologic dysfunction with elevated lactate and pyruvate
suggests impaired aerobic metabolism.
Mechanism:
Thiamine deficiency disrupts pyruvate dehydrogenase activity,
impairing entry of pyruvate into the Krebs cycle and reducing
ATP generation through oxidative phosphorylation.
Why the Correct Answer Is Right:
Neurons depend heavily on mitochondrial ATP production.
Failure of oxidative phosphorylation leads to energy depletion
and neuronal dysfunction.
Why the Other Options Are Wrong:
A. Ribosomal dysfunction impairs protein synthesis but does
not explain lactate accumulation.
C. Lysosomal degradation defects cause storage diseases rather
than acute energy failure.
D. Peroxisomal β-oxidation mainly handles very-long-chain fatty
acids.
E. Golgi dysfunction affects protein processing, not primary ATP
production.
Exam Trap (common misconception tested):
Confusing glycolysis with oxidative phosphorylation; glycolysis
remains partially active despite mitochondrial dysfunction.
,High-Yield Clinical Correlation:
Tissues with high ATP demand—brain and myocardium—are
most vulnerable to mitochondrial injury.
Q2. A researcher exposes cultured hepatocytes to a toxin that
causes dissociation of ribosomes from the rough endoplasmic
reticulum (RER). Which outcome would most likely occur first?
A. Impaired synthesis of secretory proteins
B. Failure of DNA replication
C. Increased glycogen degradation
D. Accumulation of intracellular calcium in lysosomes
E. Enhanced lipid peroxidation
Correct Answer: A
Rationale:
Clinical Clue:
Ribosomes attached to the RER synthesize proteins destined for
secretion or membrane insertion.
Mechanism:
Detachment of ribosomes interrupts translation of membrane-
bound and export proteins.
Why the Correct Answer Is Right:
The rough ER is specialized for synthesis of proteins destined
for secretion, lysosomes, or plasma membranes.
, Why the Other Options Are Wrong:
B. DNA replication occurs in the nucleus.
C. Glycogen degradation occurs in cytosolic metabolic
pathways.
D. Lysosomal calcium handling is unrelated to ribosomal
attachment.
E. Lipid peroxidation results from oxidative injury.
Exam Trap (common misconception tested):
Assuming all protein synthesis occurs independently of
organelle localization.
High-Yield Clinical Correlation:
Hepatocyte injury often manifests as impaired plasma protein
synthesis before structural failure becomes apparent.
Q3. A child with a hereditary defect in dynein arm formation
presents with recurrent respiratory infections and infertility.
The underlying cellular abnormality most directly impairs which
function?
A. ATP generation
B. Intracellular protein trafficking
C. Ciliary motility
D. Chromosomal segregation
E. Cell membrane depolarization
Correct Answer: C
Rationale:
8th Edition
Author(s)Sue E. Huether
TEST BANK
Q1. A 56-year-old man with chronic alcohol use disorder is
admitted with confusion, ataxia, and ophthalmoplegia.
Laboratory studies reveal elevated pyruvate and lactate levels.
Neuronal injury in this patient is most directly related to failure
of which cellular process?
A. Ribosomal peptide synthesis
B. Mitochondrial oxidative phosphorylation
C. Lysosomal protein degradation
D. Peroxisomal β-oxidation
E. Golgi-mediated protein packaging
Correct Answer: B
,Rationale:
Clinical Clue:
Neurologic dysfunction with elevated lactate and pyruvate
suggests impaired aerobic metabolism.
Mechanism:
Thiamine deficiency disrupts pyruvate dehydrogenase activity,
impairing entry of pyruvate into the Krebs cycle and reducing
ATP generation through oxidative phosphorylation.
Why the Correct Answer Is Right:
Neurons depend heavily on mitochondrial ATP production.
Failure of oxidative phosphorylation leads to energy depletion
and neuronal dysfunction.
Why the Other Options Are Wrong:
A. Ribosomal dysfunction impairs protein synthesis but does
not explain lactate accumulation.
C. Lysosomal degradation defects cause storage diseases rather
than acute energy failure.
D. Peroxisomal β-oxidation mainly handles very-long-chain fatty
acids.
E. Golgi dysfunction affects protein processing, not primary ATP
production.
Exam Trap (common misconception tested):
Confusing glycolysis with oxidative phosphorylation; glycolysis
remains partially active despite mitochondrial dysfunction.
,High-Yield Clinical Correlation:
Tissues with high ATP demand—brain and myocardium—are
most vulnerable to mitochondrial injury.
Q2. A researcher exposes cultured hepatocytes to a toxin that
causes dissociation of ribosomes from the rough endoplasmic
reticulum (RER). Which outcome would most likely occur first?
A. Impaired synthesis of secretory proteins
B. Failure of DNA replication
C. Increased glycogen degradation
D. Accumulation of intracellular calcium in lysosomes
E. Enhanced lipid peroxidation
Correct Answer: A
Rationale:
Clinical Clue:
Ribosomes attached to the RER synthesize proteins destined for
secretion or membrane insertion.
Mechanism:
Detachment of ribosomes interrupts translation of membrane-
bound and export proteins.
Why the Correct Answer Is Right:
The rough ER is specialized for synthesis of proteins destined
for secretion, lysosomes, or plasma membranes.
, Why the Other Options Are Wrong:
B. DNA replication occurs in the nucleus.
C. Glycogen degradation occurs in cytosolic metabolic
pathways.
D. Lysosomal calcium handling is unrelated to ribosomal
attachment.
E. Lipid peroxidation results from oxidative injury.
Exam Trap (common misconception tested):
Assuming all protein synthesis occurs independently of
organelle localization.
High-Yield Clinical Correlation:
Hepatocyte injury often manifests as impaired plasma protein
synthesis before structural failure becomes apparent.
Q3. A child with a hereditary defect in dynein arm formation
presents with recurrent respiratory infections and infertility.
The underlying cellular abnormality most directly impairs which
function?
A. ATP generation
B. Intracellular protein trafficking
C. Ciliary motility
D. Chromosomal segregation
E. Cell membrane depolarization
Correct Answer: C
Rationale:
