McCance & Huether’s Pathophysiology
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher studying rapidly dividing malignant cells
identifies a mutation that prevents degradation of cyclin
proteins during mitosis. The affected cells continue progressing
through the cell cycle despite chromosomal abnormalities. This
finding most directly reflects dysfunction of which regulatory
process?
,A. Activation of tumor suppressor genes during G0 phase
B. Proteasome-mediated control of cyclin-dependent kinase
activity
C. Increased membrane transport through gap junctions
D. Failure of sodium-potassium ATPase activity
Correct Answer: B
Rationale:
• Clinical Clue: Persistent cyclin activity with unchecked
mitosis suggests failed cell-cycle regulation.
• Mechanism: Cyclins activate cyclin-dependent kinases
(CDKs) to drive cell-cycle progression. Their degradation
via ubiquitin-proteasome pathways is necessary for
orderly transition between phases.
• Why the Correct Answer Is Right: Loss of cyclin
degradation prevents proper checkpoint control and
permits abnormal mitotic progression.
• Why the Other Options Are Wrong:
o A: Tumor suppressor dysfunction contributes to
cancer but does not specifically explain persistent
cyclin accumulation.
o C: Gap junctions coordinate cellular communication
rather than direct cell-cycle timing.
, o D: Sodium-potassium ATPase dysfunction affects
membrane potential and cell swelling, not mitotic
regulation.
• Exam Trap: Confusing general oncogenesis with the
specific biochemical control of cyclins.
• High-Yield Clinical Correlation: Cyclin-CDK dysregulation is
central to many aggressive cancers.
• Memory Anchor: “Cyclins must cycle—persistent cyclins
drive persistent division.”
Q2. A child with recurrent respiratory infections is found to
have dysfunctional dynein arms within cilia lining the
respiratory tract. Which cellular structure is primarily impaired?
A. Microfilaments
B. Intermediate filaments
C. Microtubules
D. Lysosomes
Correct Answer: C
Rationale:
• Clinical Clue: Defective ciliary movement points toward
abnormal cytoskeletal organization.
• Mechanism: Cilia contain microtubules arranged in a 9+2
pattern, with dynein arms generating movement through
ATP-dependent sliding.
, • Why the Correct Answer Is Right: Dynein-associated
motility depends directly on microtubules.
• Why the Other Options Are Wrong:
o A: Microfilaments primarily support contraction and
cell shape.
o B: Intermediate filaments provide tensile stability.
o D: Lysosomes are involved in intracellular digestion.
• Exam Trap: Associating all movement with actin
microfilaments rather than ciliary motion specifically.
• High-Yield Clinical Correlation: Primary ciliary dyskinesia
commonly presents with chronic sinusitis, bronchiectasis,
and infertility.
• Memory Anchor: “Cilia glide on microtubule tracks.”
Q3. During severe ischemia, intracellular sodium and calcium
concentrations rise while ATP levels fall sharply. The earliest
pathophysiologic change responsible for cellular swelling is
failure of which membrane process?
A. Passive diffusion across the lipid bilayer
B. Receptor-mediated endocytosis
C. Sodium-potassium ATPase transport
D. Exocytosis of intracellular proteins
Correct Answer: C
The Biologic Basis for Disease in Adults
and Children
9th Edition
Author(s)Julia Rogers
TEST BANK
Q1. A researcher studying rapidly dividing malignant cells
identifies a mutation that prevents degradation of cyclin
proteins during mitosis. The affected cells continue progressing
through the cell cycle despite chromosomal abnormalities. This
finding most directly reflects dysfunction of which regulatory
process?
,A. Activation of tumor suppressor genes during G0 phase
B. Proteasome-mediated control of cyclin-dependent kinase
activity
C. Increased membrane transport through gap junctions
D. Failure of sodium-potassium ATPase activity
Correct Answer: B
Rationale:
• Clinical Clue: Persistent cyclin activity with unchecked
mitosis suggests failed cell-cycle regulation.
• Mechanism: Cyclins activate cyclin-dependent kinases
(CDKs) to drive cell-cycle progression. Their degradation
via ubiquitin-proteasome pathways is necessary for
orderly transition between phases.
• Why the Correct Answer Is Right: Loss of cyclin
degradation prevents proper checkpoint control and
permits abnormal mitotic progression.
• Why the Other Options Are Wrong:
o A: Tumor suppressor dysfunction contributes to
cancer but does not specifically explain persistent
cyclin accumulation.
o C: Gap junctions coordinate cellular communication
rather than direct cell-cycle timing.
, o D: Sodium-potassium ATPase dysfunction affects
membrane potential and cell swelling, not mitotic
regulation.
• Exam Trap: Confusing general oncogenesis with the
specific biochemical control of cyclins.
• High-Yield Clinical Correlation: Cyclin-CDK dysregulation is
central to many aggressive cancers.
• Memory Anchor: “Cyclins must cycle—persistent cyclins
drive persistent division.”
Q2. A child with recurrent respiratory infections is found to
have dysfunctional dynein arms within cilia lining the
respiratory tract. Which cellular structure is primarily impaired?
A. Microfilaments
B. Intermediate filaments
C. Microtubules
D. Lysosomes
Correct Answer: C
Rationale:
• Clinical Clue: Defective ciliary movement points toward
abnormal cytoskeletal organization.
• Mechanism: Cilia contain microtubules arranged in a 9+2
pattern, with dynein arms generating movement through
ATP-dependent sliding.
, • Why the Correct Answer Is Right: Dynein-associated
motility depends directly on microtubules.
• Why the Other Options Are Wrong:
o A: Microfilaments primarily support contraction and
cell shape.
o B: Intermediate filaments provide tensile stability.
o D: Lysosomes are involved in intracellular digestion.
• Exam Trap: Associating all movement with actin
microfilaments rather than ciliary motion specifically.
• High-Yield Clinical Correlation: Primary ciliary dyskinesia
commonly presents with chronic sinusitis, bronchiectasis,
and infertility.
• Memory Anchor: “Cilia glide on microtubule tracks.”
Q3. During severe ischemia, intracellular sodium and calcium
concentrations rise while ATP levels fall sharply. The earliest
pathophysiologic change responsible for cellular swelling is
failure of which membrane process?
A. Passive diffusion across the lipid bilayer
B. Receptor-mediated endocytosis
C. Sodium-potassium ATPase transport
D. Exocytosis of intracellular proteins
Correct Answer: C
