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
and exercise intolerance. Muscle biopsy demonstrates
markedly reduced ATP generation despite adequate oxygen
,delivery and intact glycolytic enzymes. Electron microscopy
shows swollen organelles with disrupted cristae. The defect
most directly involves which cellular structure?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Mitochondrion
Correct Answer: D
Rationale:
• Clinical Clue: Exercise intolerance with impaired aerobic
ATP production and disrupted cristae points to
mitochondrial dysfunction.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation along the inner mitochondrial membrane.
• Why the Correct Answer Is Right: Cristae contain the
electron transport chain and ATP synthase complexes
essential for aerobic metabolism.
• Why the Other Options Are Wrong:
o A. Rough ER primarily synthesizes proteins.
o B. Golgi apparatus modifies and packages proteins.
o C. Lysosomes digest intracellular material but are not
the primary ATP source.
, • Exam Trap: Confusing generalized cellular injury with
specific mitochondrial energy failure.
• High-Yield Clinical Correlation: Mitochondrial disorders
often affect high-energy tissues such as skeletal muscle,
myocardium, and neurons.
• Memory Anchor: “Cristae create cellular energy.”
Q2. A researcher exposes cultured human cells to a toxin that
prevents assembly of microtubules during mitosis. The affected
cells fail to separate duplicated chromosomes appropriately.
Which phase of the cell cycle is most directly disrupted?
A. G1 phase
B. S phase
C. Metaphase-to-anaphase transition
D. Cytokinesis
Correct Answer: C
Rationale:
• Clinical Clue: Failure of chromosome separation after
duplication indicates spindle dysfunction.
• Mechanism: Microtubules form the mitotic spindle
responsible for chromosomal alignment and segregation.
• Why the Correct Answer Is Right: The metaphase-to-
anaphase transition requires spindle-mediated chromatid
separation.
, • Why the Other Options Are Wrong:
o A. G1 involves cell growth before DNA synthesis.
o B. S phase involves DNA replication, not chromosomal
segregation.
o D. Cytokinesis divides cytoplasm after chromosomal
separation.
• Exam Trap: Assuming DNA replication abnormalities rather
than spindle failure.
• High-Yield Clinical Correlation: Many chemotherapeutic
agents target microtubules to inhibit rapidly dividing cells.
• Memory Anchor: “Spindles split sister chromatids.”
Q3. A child with recurrent respiratory infections is found to
have defective ciliary motility caused by abnormal dynein arms.
Which cellular structure is primarily impaired?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Desmosomes
Correct Answer: B
Rationale:
• Clinical Clue: Immotile cilia due to dynein defects implicate
cytoskeletal abnormalities.
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
and exercise intolerance. Muscle biopsy demonstrates
markedly reduced ATP generation despite adequate oxygen
,delivery and intact glycolytic enzymes. Electron microscopy
shows swollen organelles with disrupted cristae. The defect
most directly involves which cellular structure?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Lysosome
D. Mitochondrion
Correct Answer: D
Rationale:
• Clinical Clue: Exercise intolerance with impaired aerobic
ATP production and disrupted cristae points to
mitochondrial dysfunction.
• Mechanism: Mitochondria generate ATP through oxidative
phosphorylation along the inner mitochondrial membrane.
• Why the Correct Answer Is Right: Cristae contain the
electron transport chain and ATP synthase complexes
essential for aerobic metabolism.
• Why the Other Options Are Wrong:
o A. Rough ER primarily synthesizes proteins.
o B. Golgi apparatus modifies and packages proteins.
o C. Lysosomes digest intracellular material but are not
the primary ATP source.
, • Exam Trap: Confusing generalized cellular injury with
specific mitochondrial energy failure.
• High-Yield Clinical Correlation: Mitochondrial disorders
often affect high-energy tissues such as skeletal muscle,
myocardium, and neurons.
• Memory Anchor: “Cristae create cellular energy.”
Q2. A researcher exposes cultured human cells to a toxin that
prevents assembly of microtubules during mitosis. The affected
cells fail to separate duplicated chromosomes appropriately.
Which phase of the cell cycle is most directly disrupted?
A. G1 phase
B. S phase
C. Metaphase-to-anaphase transition
D. Cytokinesis
Correct Answer: C
Rationale:
• Clinical Clue: Failure of chromosome separation after
duplication indicates spindle dysfunction.
• Mechanism: Microtubules form the mitotic spindle
responsible for chromosomal alignment and segregation.
• Why the Correct Answer Is Right: The metaphase-to-
anaphase transition requires spindle-mediated chromatid
separation.
, • Why the Other Options Are Wrong:
o A. G1 involves cell growth before DNA synthesis.
o B. S phase involves DNA replication, not chromosomal
segregation.
o D. Cytokinesis divides cytoplasm after chromosomal
separation.
• Exam Trap: Assuming DNA replication abnormalities rather
than spindle failure.
• High-Yield Clinical Correlation: Many chemotherapeutic
agents target microtubules to inhibit rapidly dividing cells.
• Memory Anchor: “Spindles split sister chromatids.”
Q3. A child with recurrent respiratory infections is found to
have defective ciliary motility caused by abnormal dynein arms.
Which cellular structure is primarily impaired?
A. Intermediate filaments
B. Microtubules
C. Microfilaments
D. Desmosomes
Correct Answer: B
Rationale:
• Clinical Clue: Immotile cilia due to dynein defects implicate
cytoskeletal abnormalities.
