NURS 6501 Advanced Pathophysiology
Midterm Exam Official Practice Exam
Actual Exam 2026/2027 with Detailed
Rationales | Complete Exam-Style Questions |
Pass Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: CELLULAR BIOLOGY & GENETICS Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 28-year-old woman with cystic fibrosis is found to have a ΔF508 mutation in the CFTR gene
on both alleles. Her sweat chloride is markedly elevated, and she develops recurrent
Pseudomonas aeruginosa pulmonary infections. The primary pathophysiologic defect in this
patient involves which cellular mechanism?
A. Impaired lysosomal acidification leading to defective bacterial killing
B. Defective G-protein signaling causing abnormal cAMP-mediated chloride secretion
C. Misfolded CFTR protein retained in the endoplasmic reticulum and degraded by
proteasomes ✓ CORRECT
D. Reduced mitochondrial ATP production compromising epithelial ion transport
Correct Answer: C
Rationale: The ΔF508 mutation causes a phenylalanine deletion that prevents proper CFTR
protein folding, leading to endoplasmic reticulum quality control mechanisms tagging the
protein for ubiquitination and proteasomal degradation rather than trafficking to the apical
membrane. Option B is incorrect because while CFTR is a cAMP-activated chloride channel,
the primary defect here is protein misfolding and retention, not G-protein dysfunction.
Remember that ΔF508 is the classic example of a trafficking defect, not a channel gating
defect.
Question 2 of 50
A 6-year-old boy presents with developmental delay, microcephaly, and a musty odor to his
urine. Plasma phenylalanine is 1,800 μmol/L (normal <120). His mother asks why this
happened despite no family history. The pathophysiologic mechanism most consistent with
this presentation involves which genetic principle?
,A. X-linked recessive inheritance with skewed X-inactivation in the mother
B. Autosomal recessive inheritance with compound heterozygosity for PAH mutations ✓
CORRECT
C. Autosomal dominant inheritance with incomplete penetrance of a de novo mutation
D. Mitochondrial inheritance with heteroplasmy affecting hepatic enzyme function
Correct Answer: B
Rationale: Phenylketonuria (PKU) follows autososomal recessive inheritance, and the
absence of family history is explained by compound heterozygosity where each parent carries
a different mutation in the phenylalanine hydroxylase (PAH) gene, making them asymptomatic
carriers. Option A is incorrect because PAH is located on chromosome 12 (autosomal), not
the X chromosome, and this condition shows no sex predilection. On exams, always verify
the chromosomal location before assuming X-linked inheritance for metabolic disorders.
Question 3 of 50
A 45-year-old man with chronic alcoholism develops Wernicke-Korsakoff syndrome. His
thiamine pyrophosphate-dependent enzymes show markedly reduced activity. Which cellular
process is most directly impaired by thiamine deficiency in this patient?
A. Beta-oxidation of fatty acids in hepatic mitochondria
B. Oxidative phosphorylation at Complex I of the electron transport chain
C. Decarboxylation reactions in the citric acid cycle and pentose phosphate pathway ✓
CORRECT
D. Glycogenolysis via phosphorylase kinase activation in hepatocytes
Correct Answer: C
Rationale: Thiamine pyrophosphate (TPP) serves as an essential cofactor for three key
enzymes: pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase, all of
which catalyze decarboxylation reactions critical for aerobic metabolism and ribose
synthesis. Option A is incorrect because beta-oxidation depends on FAD and NAD+
cofactors, not TPP, and fatty acid oxidation defects present with hypoketotic hypoglycemia
rather than neurologic Wernicke triad. Focus on the three TPP-dependent enzymes when
evaluating thiamine deficiency scenarios.
Question 4 of 50
A 32-year-old woman with BRCA1 mutation-associated breast cancer receives neoadjuvant
chemotherapy. Her tumor shows high-grade features and triple-negative phenotype. Which
molecular mechanism best explains why BRCA1-deficient tumors are particularly sensitive to
platinum agents and PARP inhibitors?
A. Upregulation of angiogenic factors increasing drug delivery to tumor cells
, B. Defective homologous recombination repair causing synthetic lethality with PARP
inhibition ✓ CORRECT
C. Enhanced apoptosis via p53-independent pathways activated by DNA crosslinking
D. Increased membrane permeability allowing greater intracellular drug accumulation
Correct Answer: B
Rationale: BRCA1 is essential for homologous recombination (HR) repair of double-strand
DNA breaks, and its loss creates reliance on error-prone non-homologous end joining; PARP
inhibitors block base excision repair, and in HR-deficient cells, this creates synthetic lethality
because neither repair pathway functions. Option C is incorrect because BRCA1-associated
tumors actually show impaired p53-mediated apoptosis due to genomic instability, and
platinum sensitivity arises from inability to repair interstrand crosslinks, not enhanced
apoptosis. Synthetic lethality is the foundational concept underlying targeted therapy in
BRCA-mutant cancers.
Question 5 of 50
A 55-year-old man with multiple myeloma receives bortezomib, a proteasome inhibitor. After
two cycles, he develops peripheral neuropathy and orthostatic hypotension. The therapeutic
effect of bortezomib in myeloma is best explained by interference with which cellular
process?
A. Inhibition of NF-κB activation by preventing IκB degradation ✓ CORRECT
B. Blockade of mTOR signaling preventing protein synthesis in malignant plasma cells
C. Prevention of histone deacetylation causing cell cycle arrest in G2/M phase
D. Inhibition of BCL-2 anti-apoptotic proteins triggering intrinsic pathway apoptosis
Correct Answer: A
Rationale: Bortezomib inhibits the 26S proteasome, preventing degradation of IκB (the
inhibitor of NF-κB), which sequesters NF-κB in the cytoplasm and blocks its nuclear
translocation; since NF-κB promotes myeloma cell survival, proliferation, and IL-6 production,
its inhibition induces apoptosis. Option D is incorrect because BCL-2 inhibition is the
mechanism of venetoclax, not bortezomib, and myeloma cells are more dependent on
NF-κB-driven survival signals than BCL-2 overexpression. Distinguish proteasome inhibitor
mechanisms from other targeted agents by focusing on the ubiquitin-proteasome pathway.
Question 6 of 50
A 3-year-old girl is diagnosed with osteogenesis imperfecta type I after multiple fractures
with minimal trauma. Genetic testing reveals a COL1A1 nonsense mutation. Which
pathophysiologic mechanism best explains the bone fragility in this patient?
A. Defective osteoclast-mediated bone resorption causing excessive bone density
B. Impaired cross-linking of collagen fibrils due to lysyl hydroxylase deficiency
Midterm Exam Official Practice Exam
Actual Exam 2026/2027 with Detailed
Rationales | Complete Exam-Style Questions |
Pass Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: CELLULAR BIOLOGY & GENETICS Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 28-year-old woman with cystic fibrosis is found to have a ΔF508 mutation in the CFTR gene
on both alleles. Her sweat chloride is markedly elevated, and she develops recurrent
Pseudomonas aeruginosa pulmonary infections. The primary pathophysiologic defect in this
patient involves which cellular mechanism?
A. Impaired lysosomal acidification leading to defective bacterial killing
B. Defective G-protein signaling causing abnormal cAMP-mediated chloride secretion
C. Misfolded CFTR protein retained in the endoplasmic reticulum and degraded by
proteasomes ✓ CORRECT
D. Reduced mitochondrial ATP production compromising epithelial ion transport
Correct Answer: C
Rationale: The ΔF508 mutation causes a phenylalanine deletion that prevents proper CFTR
protein folding, leading to endoplasmic reticulum quality control mechanisms tagging the
protein for ubiquitination and proteasomal degradation rather than trafficking to the apical
membrane. Option B is incorrect because while CFTR is a cAMP-activated chloride channel,
the primary defect here is protein misfolding and retention, not G-protein dysfunction.
Remember that ΔF508 is the classic example of a trafficking defect, not a channel gating
defect.
Question 2 of 50
A 6-year-old boy presents with developmental delay, microcephaly, and a musty odor to his
urine. Plasma phenylalanine is 1,800 μmol/L (normal <120). His mother asks why this
happened despite no family history. The pathophysiologic mechanism most consistent with
this presentation involves which genetic principle?
,A. X-linked recessive inheritance with skewed X-inactivation in the mother
B. Autosomal recessive inheritance with compound heterozygosity for PAH mutations ✓
CORRECT
C. Autosomal dominant inheritance with incomplete penetrance of a de novo mutation
D. Mitochondrial inheritance with heteroplasmy affecting hepatic enzyme function
Correct Answer: B
Rationale: Phenylketonuria (PKU) follows autososomal recessive inheritance, and the
absence of family history is explained by compound heterozygosity where each parent carries
a different mutation in the phenylalanine hydroxylase (PAH) gene, making them asymptomatic
carriers. Option A is incorrect because PAH is located on chromosome 12 (autosomal), not
the X chromosome, and this condition shows no sex predilection. On exams, always verify
the chromosomal location before assuming X-linked inheritance for metabolic disorders.
Question 3 of 50
A 45-year-old man with chronic alcoholism develops Wernicke-Korsakoff syndrome. His
thiamine pyrophosphate-dependent enzymes show markedly reduced activity. Which cellular
process is most directly impaired by thiamine deficiency in this patient?
A. Beta-oxidation of fatty acids in hepatic mitochondria
B. Oxidative phosphorylation at Complex I of the electron transport chain
C. Decarboxylation reactions in the citric acid cycle and pentose phosphate pathway ✓
CORRECT
D. Glycogenolysis via phosphorylase kinase activation in hepatocytes
Correct Answer: C
Rationale: Thiamine pyrophosphate (TPP) serves as an essential cofactor for three key
enzymes: pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase, all of
which catalyze decarboxylation reactions critical for aerobic metabolism and ribose
synthesis. Option A is incorrect because beta-oxidation depends on FAD and NAD+
cofactors, not TPP, and fatty acid oxidation defects present with hypoketotic hypoglycemia
rather than neurologic Wernicke triad. Focus on the three TPP-dependent enzymes when
evaluating thiamine deficiency scenarios.
Question 4 of 50
A 32-year-old woman with BRCA1 mutation-associated breast cancer receives neoadjuvant
chemotherapy. Her tumor shows high-grade features and triple-negative phenotype. Which
molecular mechanism best explains why BRCA1-deficient tumors are particularly sensitive to
platinum agents and PARP inhibitors?
A. Upregulation of angiogenic factors increasing drug delivery to tumor cells
, B. Defective homologous recombination repair causing synthetic lethality with PARP
inhibition ✓ CORRECT
C. Enhanced apoptosis via p53-independent pathways activated by DNA crosslinking
D. Increased membrane permeability allowing greater intracellular drug accumulation
Correct Answer: B
Rationale: BRCA1 is essential for homologous recombination (HR) repair of double-strand
DNA breaks, and its loss creates reliance on error-prone non-homologous end joining; PARP
inhibitors block base excision repair, and in HR-deficient cells, this creates synthetic lethality
because neither repair pathway functions. Option C is incorrect because BRCA1-associated
tumors actually show impaired p53-mediated apoptosis due to genomic instability, and
platinum sensitivity arises from inability to repair interstrand crosslinks, not enhanced
apoptosis. Synthetic lethality is the foundational concept underlying targeted therapy in
BRCA-mutant cancers.
Question 5 of 50
A 55-year-old man with multiple myeloma receives bortezomib, a proteasome inhibitor. After
two cycles, he develops peripheral neuropathy and orthostatic hypotension. The therapeutic
effect of bortezomib in myeloma is best explained by interference with which cellular
process?
A. Inhibition of NF-κB activation by preventing IκB degradation ✓ CORRECT
B. Blockade of mTOR signaling preventing protein synthesis in malignant plasma cells
C. Prevention of histone deacetylation causing cell cycle arrest in G2/M phase
D. Inhibition of BCL-2 anti-apoptotic proteins triggering intrinsic pathway apoptosis
Correct Answer: A
Rationale: Bortezomib inhibits the 26S proteasome, preventing degradation of IκB (the
inhibitor of NF-κB), which sequesters NF-κB in the cytoplasm and blocks its nuclear
translocation; since NF-κB promotes myeloma cell survival, proliferation, and IL-6 production,
its inhibition induces apoptosis. Option D is incorrect because BCL-2 inhibition is the
mechanism of venetoclax, not bortezomib, and myeloma cells are more dependent on
NF-κB-driven survival signals than BCL-2 overexpression. Distinguish proteasome inhibitor
mechanisms from other targeted agents by focusing on the ubiquitin-proteasome pathway.
Question 6 of 50
A 3-year-old girl is diagnosed with osteogenesis imperfecta type I after multiple fractures
with minimal trauma. Genetic testing reveals a COL1A1 nonsense mutation. Which
pathophysiologic mechanism best explains the bone fragility in this patient?
A. Defective osteoclast-mediated bone resorption causing excessive bone density
B. Impaired cross-linking of collagen fibrils due to lysyl hydroxylase deficiency
