Advanced Pathophysiology MCQs
Section 0:
1. Which of the following is the most common mechanism by which hypoxia
causes cellular injury?
A. Increased ATP production
B. Decreased ATP production disrupting ion pumps
C. Increased protein synthesis
D. Enhanced mitochondrial function
✅Rationale:
Correct Answer: B. Decreased ATP production disrupting ion pumps
Hypoxia reduces oxidative phosphorylation in mitochondria,
lowering ATP. This impairs Na⁺/K⁺ ATPase pumps, leading to sodium and
water influx → cell swelling. The other options are not associated with
hypoxic injury mechanisms.
2. Which statement best differentiates apoptosis from necrosis?
A. Apoptosis always causes inflammation.
B. Necrosis involves controlled removal of cells.
C. Apoptosis maintains membrane integrity, necrosis does not.
D. Necrosis is always physiological.
✅ Correct Answer: C. Apoptosis maintains membrane integrity, necrosis
does not
Rationale: In apoptosis, membranes stay intact while the cell is dismantled
into apoptotic bodies; necrosis involves membrane rupture and inflammation.
3. During ischemia-reperfusion injury, which factor primarily causes
additional damage after oxygen is restored?
A. Decreased ROS
B. Excess ROS generation
C. Loss of lysosomal enzymes
D. Decreased calcium influx
✅Rationale:
Correct Answer: B. Excess ROS generation
Reintroduction of oxygen increases electron leakage from
mitochondria, producing reactive oxygen species that damage lipids, proteins,
and DNA.
,4. Free radicals damage cell membranes primarily through which process?
A. Protein denaturation
B. DNA methylation
C. Lipid peroxidation
D. Phagocytosis
✅Rationale:
Correct Answer: C. Lipid peroxidation
ROS attack polyunsaturated fatty acids in membranes, initiating
chain reactions that disrupt integrity and function.
5. Which mitochondrial change is most associated with irreversible cell
injury?
A. ATP overproduction
B. Mitochondrial permeability transition pore opening
C. Increased mitochondrial calcium storage
D. Increased protein folding
✅Rationale:
Correct Answer: B. Mitochondrial permeability transition pore opening
Pore opening collapses the proton gradient, halts ATP synthesis,
and triggers necrosis or apoptosis.
Section 1 – Cellular and Molecular Pathophysiology
1. Which is the primary effect of hypoxia on cells?
A. Increased protein synthesis
B. Decreased ATP production disrupting ion pumps
C. Activation of caspases
D. Lysosomal enzyme leakage
✅Rationale:
Correct Answer: B. Decreased ATP production disrupting ion pumps
Hypoxia impairs oxidative phosphorylation in mitochondria,
reducing ATP, which disrupts Na⁺/K⁺ ATPase and causes cell swelling.
2. Which cellular adaptation involves an increase in cell number?
A. Hypertrophy
B. Atrophy
C. Hyperplasia
D. Metaplasia
,✅Rationale:
Correct Answer: C. Hyperplasia
Hyperplasia is an increase in the number of cells; hypertrophy is
an increase in size, atrophy is a decrease in size/number, and metaplasia is
cell type replacement.
3. What is a key difference between necrosis and apoptosis?
A. Necrosis is always physiological
B. Apoptosis involves membrane rupture
C. Apoptosis maintains membrane integrity
D. Necrosis involves caspase activation
✅Rationale:
Correct Answer: C. Apoptosis maintains membrane integrity
Apoptosis is a controlled process with intact membranes; necrosis
disrupts membranes and causes inflammation.
4. Which process during reperfusion injury causes the most damage?
A. Reduced nitric oxide
B. Overproduction of reactive oxygen species
C. Protein synthesis increase
D. Decreased calcium influx
✅Rationale:
Correct Answer: B. Overproduction of reactive oxygen species
Oxygen reintroduction increases mitochondrial electron leakage,
producing ROS that damage lipids, proteins, and DNA.
5. Free radicals cause membrane damage primarily by:
A. Lipid peroxidation
B. Protein denaturation
C. DNA methylation
D. Phagocytosis
✅Rationale:
Correct Answer: A. Lipid peroxidation
ROS attack unsaturated fatty acids in cell membranes, initiating
chain reactions that disrupt integrity.
6. Which mitochondrial change signals irreversible injury?
A. Increased ATP production
B. Mitochondrial permeability transition pore opening
, C. Calcium buffering
D. Enhanced protein folding
✅Rationale:
Correct Answer: B. Mitochondrial permeability transition pore opening
This causes loss of proton gradient, halts ATP synthesis, and
releases pro-apoptotic factors.
7. Which best describes autophagy?
A. Protein synthesis increase
B. Formation of autophagosomes to degrade damaged organelles
C. Necrosis of lysosomes
D. Apoptotic DNA fragmentation
✅ Correct Answer: B. Formation of autophagosomes to degrade damaged
organelles
Rationale: Autophagy sequesters damaged components in vesicles that fuse
with lysosomes for recycling.
8. Which occurs when the Unfolded Protein Response (UPR) fails during ER
stress?
A. Increased protein folding
B. Apoptosis
C. Autophagy
D. Necrosis only
✅Rationale:
Correct Answer: B. Apoptosis
Persistent misfolded proteins activate CHOP and caspases,
leading to programmed cell death.
9. Oxidative stress results from:
A. Excess antioxidants
B. Imbalance between ROS production and antioxidant defenses
C. Increased apoptosis
D. Mitochondrial swelling only
✅ Correct Answer: B. Imbalance between ROS production and antioxidant
defenses
Rationale: ROS accumulate when production exceeds neutralization,
damaging DNA, proteins, and lipids.
Section 0:
1. Which of the following is the most common mechanism by which hypoxia
causes cellular injury?
A. Increased ATP production
B. Decreased ATP production disrupting ion pumps
C. Increased protein synthesis
D. Enhanced mitochondrial function
✅Rationale:
Correct Answer: B. Decreased ATP production disrupting ion pumps
Hypoxia reduces oxidative phosphorylation in mitochondria,
lowering ATP. This impairs Na⁺/K⁺ ATPase pumps, leading to sodium and
water influx → cell swelling. The other options are not associated with
hypoxic injury mechanisms.
2. Which statement best differentiates apoptosis from necrosis?
A. Apoptosis always causes inflammation.
B. Necrosis involves controlled removal of cells.
C. Apoptosis maintains membrane integrity, necrosis does not.
D. Necrosis is always physiological.
✅ Correct Answer: C. Apoptosis maintains membrane integrity, necrosis
does not
Rationale: In apoptosis, membranes stay intact while the cell is dismantled
into apoptotic bodies; necrosis involves membrane rupture and inflammation.
3. During ischemia-reperfusion injury, which factor primarily causes
additional damage after oxygen is restored?
A. Decreased ROS
B. Excess ROS generation
C. Loss of lysosomal enzymes
D. Decreased calcium influx
✅Rationale:
Correct Answer: B. Excess ROS generation
Reintroduction of oxygen increases electron leakage from
mitochondria, producing reactive oxygen species that damage lipids, proteins,
and DNA.
,4. Free radicals damage cell membranes primarily through which process?
A. Protein denaturation
B. DNA methylation
C. Lipid peroxidation
D. Phagocytosis
✅Rationale:
Correct Answer: C. Lipid peroxidation
ROS attack polyunsaturated fatty acids in membranes, initiating
chain reactions that disrupt integrity and function.
5. Which mitochondrial change is most associated with irreversible cell
injury?
A. ATP overproduction
B. Mitochondrial permeability transition pore opening
C. Increased mitochondrial calcium storage
D. Increased protein folding
✅Rationale:
Correct Answer: B. Mitochondrial permeability transition pore opening
Pore opening collapses the proton gradient, halts ATP synthesis,
and triggers necrosis or apoptosis.
Section 1 – Cellular and Molecular Pathophysiology
1. Which is the primary effect of hypoxia on cells?
A. Increased protein synthesis
B. Decreased ATP production disrupting ion pumps
C. Activation of caspases
D. Lysosomal enzyme leakage
✅Rationale:
Correct Answer: B. Decreased ATP production disrupting ion pumps
Hypoxia impairs oxidative phosphorylation in mitochondria,
reducing ATP, which disrupts Na⁺/K⁺ ATPase and causes cell swelling.
2. Which cellular adaptation involves an increase in cell number?
A. Hypertrophy
B. Atrophy
C. Hyperplasia
D. Metaplasia
,✅Rationale:
Correct Answer: C. Hyperplasia
Hyperplasia is an increase in the number of cells; hypertrophy is
an increase in size, atrophy is a decrease in size/number, and metaplasia is
cell type replacement.
3. What is a key difference between necrosis and apoptosis?
A. Necrosis is always physiological
B. Apoptosis involves membrane rupture
C. Apoptosis maintains membrane integrity
D. Necrosis involves caspase activation
✅Rationale:
Correct Answer: C. Apoptosis maintains membrane integrity
Apoptosis is a controlled process with intact membranes; necrosis
disrupts membranes and causes inflammation.
4. Which process during reperfusion injury causes the most damage?
A. Reduced nitric oxide
B. Overproduction of reactive oxygen species
C. Protein synthesis increase
D. Decreased calcium influx
✅Rationale:
Correct Answer: B. Overproduction of reactive oxygen species
Oxygen reintroduction increases mitochondrial electron leakage,
producing ROS that damage lipids, proteins, and DNA.
5. Free radicals cause membrane damage primarily by:
A. Lipid peroxidation
B. Protein denaturation
C. DNA methylation
D. Phagocytosis
✅Rationale:
Correct Answer: A. Lipid peroxidation
ROS attack unsaturated fatty acids in cell membranes, initiating
chain reactions that disrupt integrity.
6. Which mitochondrial change signals irreversible injury?
A. Increased ATP production
B. Mitochondrial permeability transition pore opening
, C. Calcium buffering
D. Enhanced protein folding
✅Rationale:
Correct Answer: B. Mitochondrial permeability transition pore opening
This causes loss of proton gradient, halts ATP synthesis, and
releases pro-apoptotic factors.
7. Which best describes autophagy?
A. Protein synthesis increase
B. Formation of autophagosomes to degrade damaged organelles
C. Necrosis of lysosomes
D. Apoptotic DNA fragmentation
✅ Correct Answer: B. Formation of autophagosomes to degrade damaged
organelles
Rationale: Autophagy sequesters damaged components in vesicles that fuse
with lysosomes for recycling.
8. Which occurs when the Unfolded Protein Response (UPR) fails during ER
stress?
A. Increased protein folding
B. Apoptosis
C. Autophagy
D. Necrosis only
✅Rationale:
Correct Answer: B. Apoptosis
Persistent misfolded proteins activate CHOP and caspases,
leading to programmed cell death.
9. Oxidative stress results from:
A. Excess antioxidants
B. Imbalance between ROS production and antioxidant defenses
C. Increased apoptosis
D. Mitochondrial swelling only
✅ Correct Answer: B. Imbalance between ROS production and antioxidant
defenses
Rationale: ROS accumulate when production exceeds neutralization,
damaging DNA, proteins, and lipids.
