NR 507 Advanced Pathophysiology Midterm
Exam Official Practice Exam Actual Exam
2026/2027 with Detailed Rationales | Complete
Exam-Style Questions | Pass Guaranteed – A+
Graded
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SECTION 1: CELLULAR BIOLOGY & GENETICS Q1 – Q10
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Question 1 of 50
A 58-year-old male with a 40 pack-year smoking history presents with hemoptysis and a 3 cm
right upper lobe mass. Biopsy reveals non-small cell lung carcinoma. Molecular analysis
shows a missense mutation in a tumor suppressor gene that normally halts cell cycle
progression in response to DNA double-strand breaks. Which pathophysiologic mechanism
is most directly impaired by this mutation?
A. Activation of cyclin-dependent kinases independent of checkpoint control
B. Transcription of p21 leading to G1/S cell cycle arrest
C. Degradation of Bcl-2 to promote intrinsic apoptosis
D. Phosphorylation of Rb protein by cyclin D/Cdk4 complexes
Correct Answer: B
Rationale: Wild-type p53 detects DNA damage and transcriptionally upregulates p21, a Cdk
inhibitor that enforces G1/S checkpoint arrest to allow repair or trigger apoptosis. Option A
describes a mechanism driven by oncogenes such as cyclin E overexpression, not the
primary defect caused by p53 loss. In advanced lung cancer, p53 mutations are among the
most common driver alterations disrupting this checkpoint logic.
Question 2 of 50
A 6-month-old male is evaluated for failure to thrive, steatorrhea, and a salty taste to his skin.
Sweat chloride testing returns 92 mmol/L. Genetic testing confirms homozygosity for the
ΔF508 mutation. Which cellular transport defect underlies the pathophysiology of his
gastrointestinal and pulmonary manifestations?
A. Impaired sodium reabsorption via epithelial ENaC channels
,B. Defective chloride secretion due to misfolded CFTR protein retention in the Golgi
apparatus
C. Loss of aquaporin-5 function in respiratory epithelial cells
D. Dysfunctional bile salt export pump leading to cholestatic injury
Correct Answer: B
Rationale: The ΔF508 mutation produces a misfolded CFTR protein that is retained by the
endoplasmic reticulum quality control system and degraded before reaching the apical
membrane, abolishing cAMP-mediated chloride secretion and secondarily increasing
ENaC-mediated sodium absorption. Option A inverts the mechanism; ENaC hyperactivity is a
downstream consequence, not the primary defect. This ionic imbalance reduces airway
surface liquid and increases mucus viscosity.
Question 3 of 50
A 45-year-old female with BRCA1 positivity undergoes prophylactic bilateral mastectomy.
Pathology incidentally identifies a 4 mm focus of ductal carcinoma in situ with markedly
elevated telomerase activity on immunohistochemistry. Which cellular process is most
directly enabled by this telomerase reactivation in her early malignancy?
A. Bypass of replicative senescence through maintenance of telomere length
B. Enhanced double-strand break repair via homologous recombination
C. Increased mitochondrial biogenesis and oxidative phosphorylation
D. Activation of cyclin D1 transcription via Wnt/β-catenin signaling
Correct Answer: A
Rationale: Telomerase synthesizes telomeric DNA via its hTERT reverse transcriptase
component, compensating for end-replication loss and allowing malignant cells to achieve
replicative immortality. Option B conflates telomerase with BRCA1-mediated homologous
recombination repair, which is a separate DNA maintenance pathway. Telomerase
reactivation is detectable in approximately 90% of human cancers and represents a hallmark
of malignant transformation.
Question 4 of 50
A 62-year-old male with metastatic colon cancer develops tumor lysis syndrome after initial
chemotherapy. Laboratory studies reveal hyperkalemia, hyperphosphatemia, and
hypocalcemia. His oncologist is concerned about acute kidney injury from uric acid crystal
deposition. Which form of cell death is most likely responsible for the massive electrolyte
release observed in this syndrome?
A. Apoptosis with intact membrane blebbing and phagocytic clearance
B. Necroptosis driven by RIPK1/RIPK3 mixed lineage kinase domain-like pseudokinase
activation
, C. Oncosis secondary to ATP depletion and loss of ion pump function
D. Pyroptosis mediated by caspase-1 cleavage of gasdermin D
Correct Answer: C
Rationale: Tumor lysis syndrome produces oncotic cell death characterized by ATP depletion,
cell swelling, organelle dysfunction, and rupture of the plasma membrane, releasing
intracellular contents into the extracellular space. Option A is incorrect because apoptosis
preserves membrane integrity and does not cause the massive electrolyte efflux seen here.
The rapid lysis of bulky tumor cells overwhelms renal clearance capacity, precipitating uric
acid and calcium phosphate crystals.
Question 5 of 50
A 38-year-old female with a family history of endometrial and colorectal cancers undergoes
genetic counseling. Microsatellite instability testing on her endometrial biopsy is positive.
Sequencing reveals a pathogenic variant in a DNA mismatch repair gene. Which molecular
consequence most directly drives carcinogenesis in this patient?
A. Accumulation of point mutations in KRAS and BRAF oncogenes
B. Expansion of microsatellite repeats and frameshift mutations in tumor suppressor genes
C. Global hypomethylation of CpG islands leading to chromosomal instability
D. Defective homologous recombination causing gross chromosomal rearrangements
Correct Answer: B
Rationale: Mismatch repair deficiency permits slippage errors during DNA replication to
persist, producing microsatellite instability and frameshift mutations in genes with coding
microsatellites such as TGFBR2 and BAX. Option A describes the typical mutation profile of
sporadic microsatellite-stable colorectal cancers driven by APC-KRAS-TP53 progression.
Lynch syndrome, caused by MLH1, MSH2, MSH6, or PMS2 mutations, accounts for the
majority of hereditary mismatch repair-deficient cancers.
Question 6 of 50
A 55-year-old male with newly diagnosed pancreatic cancer and significant cachexia
demonstrates prominent autophagic vacuoles on electron microscopy of skeletal muscle
biopsy. His oncologist explains that the tumor is inducing a catabolic state. Which
pathophysiologic role best explains why autophagy is upregulated in his skeletal muscle?
A. Lysosomal degradation of bulk cytoplasmic contents to fuel mitochondrial oxidative
metabolism
B. Activation of the ubiquitin-proteasome system for selective protein turnover
C. Inhibition of mTORC1 signaling leading to ribosomal biogenesis and protein synthesis
D. Sequestration of reactive oxygen species within peroxisomal catalase compartments
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 58-year-old male with a 40 pack-year smoking history presents with hemoptysis and a 3 cm
right upper lobe mass. Biopsy reveals non-small cell lung carcinoma. Molecular analysis
shows a missense mutation in a tumor suppressor gene that normally halts cell cycle
progression in response to DNA double-strand breaks. Which pathophysiologic mechanism
is most directly impaired by this mutation?
A. Activation of cyclin-dependent kinases independent of checkpoint control
B. Transcription of p21 leading to G1/S cell cycle arrest
C. Degradation of Bcl-2 to promote intrinsic apoptosis
D. Phosphorylation of Rb protein by cyclin D/Cdk4 complexes
Correct Answer: B
Rationale: Wild-type p53 detects DNA damage and transcriptionally upregulates p21, a Cdk
inhibitor that enforces G1/S checkpoint arrest to allow repair or trigger apoptosis. Option A
describes a mechanism driven by oncogenes such as cyclin E overexpression, not the
primary defect caused by p53 loss. In advanced lung cancer, p53 mutations are among the
most common driver alterations disrupting this checkpoint logic.
Question 2 of 50
A 6-month-old male is evaluated for failure to thrive, steatorrhea, and a salty taste to his skin.
Sweat chloride testing returns 92 mmol/L. Genetic testing confirms homozygosity for the
ΔF508 mutation. Which cellular transport defect underlies the pathophysiology of his
gastrointestinal and pulmonary manifestations?
A. Impaired sodium reabsorption via epithelial ENaC channels
,B. Defective chloride secretion due to misfolded CFTR protein retention in the Golgi
apparatus
C. Loss of aquaporin-5 function in respiratory epithelial cells
D. Dysfunctional bile salt export pump leading to cholestatic injury
Correct Answer: B
Rationale: The ΔF508 mutation produces a misfolded CFTR protein that is retained by the
endoplasmic reticulum quality control system and degraded before reaching the apical
membrane, abolishing cAMP-mediated chloride secretion and secondarily increasing
ENaC-mediated sodium absorption. Option A inverts the mechanism; ENaC hyperactivity is a
downstream consequence, not the primary defect. This ionic imbalance reduces airway
surface liquid and increases mucus viscosity.
Question 3 of 50
A 45-year-old female with BRCA1 positivity undergoes prophylactic bilateral mastectomy.
Pathology incidentally identifies a 4 mm focus of ductal carcinoma in situ with markedly
elevated telomerase activity on immunohistochemistry. Which cellular process is most
directly enabled by this telomerase reactivation in her early malignancy?
A. Bypass of replicative senescence through maintenance of telomere length
B. Enhanced double-strand break repair via homologous recombination
C. Increased mitochondrial biogenesis and oxidative phosphorylation
D. Activation of cyclin D1 transcription via Wnt/β-catenin signaling
Correct Answer: A
Rationale: Telomerase synthesizes telomeric DNA via its hTERT reverse transcriptase
component, compensating for end-replication loss and allowing malignant cells to achieve
replicative immortality. Option B conflates telomerase with BRCA1-mediated homologous
recombination repair, which is a separate DNA maintenance pathway. Telomerase
reactivation is detectable in approximately 90% of human cancers and represents a hallmark
of malignant transformation.
Question 4 of 50
A 62-year-old male with metastatic colon cancer develops tumor lysis syndrome after initial
chemotherapy. Laboratory studies reveal hyperkalemia, hyperphosphatemia, and
hypocalcemia. His oncologist is concerned about acute kidney injury from uric acid crystal
deposition. Which form of cell death is most likely responsible for the massive electrolyte
release observed in this syndrome?
A. Apoptosis with intact membrane blebbing and phagocytic clearance
B. Necroptosis driven by RIPK1/RIPK3 mixed lineage kinase domain-like pseudokinase
activation
, C. Oncosis secondary to ATP depletion and loss of ion pump function
D. Pyroptosis mediated by caspase-1 cleavage of gasdermin D
Correct Answer: C
Rationale: Tumor lysis syndrome produces oncotic cell death characterized by ATP depletion,
cell swelling, organelle dysfunction, and rupture of the plasma membrane, releasing
intracellular contents into the extracellular space. Option A is incorrect because apoptosis
preserves membrane integrity and does not cause the massive electrolyte efflux seen here.
The rapid lysis of bulky tumor cells overwhelms renal clearance capacity, precipitating uric
acid and calcium phosphate crystals.
Question 5 of 50
A 38-year-old female with a family history of endometrial and colorectal cancers undergoes
genetic counseling. Microsatellite instability testing on her endometrial biopsy is positive.
Sequencing reveals a pathogenic variant in a DNA mismatch repair gene. Which molecular
consequence most directly drives carcinogenesis in this patient?
A. Accumulation of point mutations in KRAS and BRAF oncogenes
B. Expansion of microsatellite repeats and frameshift mutations in tumor suppressor genes
C. Global hypomethylation of CpG islands leading to chromosomal instability
D. Defective homologous recombination causing gross chromosomal rearrangements
Correct Answer: B
Rationale: Mismatch repair deficiency permits slippage errors during DNA replication to
persist, producing microsatellite instability and frameshift mutations in genes with coding
microsatellites such as TGFBR2 and BAX. Option A describes the typical mutation profile of
sporadic microsatellite-stable colorectal cancers driven by APC-KRAS-TP53 progression.
Lynch syndrome, caused by MLH1, MSH2, MSH6, or PMS2 mutations, accounts for the
majority of hereditary mismatch repair-deficient cancers.
Question 6 of 50
A 55-year-old male with newly diagnosed pancreatic cancer and significant cachexia
demonstrates prominent autophagic vacuoles on electron microscopy of skeletal muscle
biopsy. His oncologist explains that the tumor is inducing a catabolic state. Which
pathophysiologic role best explains why autophagy is upregulated in his skeletal muscle?
A. Lysosomal degradation of bulk cytoplasmic contents to fuel mitochondrial oxidative
metabolism
B. Activation of the ubiquitin-proteasome system for selective protein turnover
C. Inhibition of mTORC1 signaling leading to ribosomal biogenesis and protein synthesis
D. Sequestration of reactive oxygen species within peroxisomal catalase compartments
