NR 507 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
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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 2-cm
hilar mass. Biopsy reveals small cell lung cancer. Molecular testing shows loss of
heterozygosity at chromosome 17p13.1. The tumor's uncontrolled proliferation is most
directly caused by which molecular mechanism?
A. Inactivation of the RB tumor suppressor gene leading to unregulated G1/S checkpoint
progression
B. Loss of p53-mediated DNA damage surveillance and apoptosis induction ✓ CORRECT
C. Constitutive activation of the RAS-MAPK signaling cascade driving continuous mitogenic
signals
D. Overexpression of telomerase preventing cellular senescence and enabling replicative
immortality
Correct Answer: B
Rationale: p53, encoded at 17p13.1, functions as the guardian of the genome by arresting the
cell cycle in response to DNA damage and initiating apoptosis when repair fails; loss of this
surveillance permits malignant cells with genomic instability to survive and proliferate. RB
inactivation is characteristic of small cell lung cancer but primarily governs G1/S transition
rather than DNA damage response, making it a tempting distractor because both are tumor
suppressors frequently implicated in lung cancer. On the exam, remember that chromosome
17p13.1 specifically localizes to p53, not RB, which resides on chromosome 13q14.
Question 2 of 50
A 24-year-old woman with a family history of breast cancer undergoes genetic counseling.
Her mother and maternal aunt both developed breast cancer before age 45. Genetic testing
,reveals a pathogenic variant in a gene responsible for homologous recombination repair.
Which cellular process is most directly impaired by this mutation?
A. Nucleotide excision repair of ultraviolet-induced thymine dimers
B. Base excision repair correcting oxidative damage to single bases
C. Mismatch repair correcting errors in DNA replication
D. Homologous recombination repair of double-strand DNA breaks ✓ CORRECT
Correct Answer: D
Rationale: BRCA1 and BRCA2 are tumor suppressor genes that mediate high-fidelity
homologous recombination repair of double-strand DNA breaks; loss of this function leads
to genomic instability and accumulation of mutations that drive carcinogenesis. Nucleotide
excision repair defects cause xeroderma pigmentosum, not hereditary breast cancer, and
students often confuse this because both are DNA repair mechanisms. The key exam clue is
the early-onset familial breast cancer pattern, which strongly suggests BRCA-related
homologous recombination deficiency rather than other repair pathway defects.
Question 3 of 50
A 62-year-old male with chronic hypertension has left ventricular hypertrophy on
echocardiogram. Myocardial biopsy demonstrates enlarged cardiac myocytes with increased
nuclear size but no increase in cell number. Which cellular adaptation is demonstrated?
A. Physiologic hypertrophy driven by increased synthesis of contractile proteins ✓ CORRECT
B. Pathologic hyperplasia resulting from growth factor-mediated myocyte proliferation
C. Metaplasia of cardiac myocytes into a more resistant fibroblast phenotype
D. Dysplasia characterized by disordered cellular architecture and nuclear pleomorphism
Correct Answer: A
Rationale: Cardiac myocytes are terminally differentiated cells incapable of mitosis, so
chronic pressure overload induces hypertrophy through increased protein synthesis and
sarcomere assembly rather than hyperplasia. Hyperplasia is incorrect because adult cardiac
myocytes do not divide, and this distractor targets the common misconception that
increased organ size always reflects increased cell number. Remember that hypertrophy
increases cell size while hyperplasia increases cell number, and cardiac tissue predominantly
hypertrophies in response to hemodynamic stress.
Question 4 of 50
A 45-year-old woman presents with progressive dyspnea and dry cough. High-resolution CT
shows honeycombing and traction bronchiectasis. Lung biopsy reveals fibroblastic foci and
excessive extracellular matrix deposition. Which molecular mechanism primarily drives this
pathologic tissue remodeling?
, A. Persistent activation of the PI3K-Akt pathway promoting cellular proliferation
B. Deficiency of alpha-1 antitrypsin leading to unopposed neutrophil elastase activity
C. Dysregulated TGF-β signaling stimulating fibroblast-to-myofibroblast differentiation ✓
CORRECT
D. Excessive VEGF production promoting abnormal angiogenesis within fibrotic lesions
Correct Answer: C
Rationale: Idiopathic pulmonary fibrosis is characterized by aberrant wound healing in which
TGF-β perpetually activates fibroblasts, driving their differentiation into contractile
myofibroblasts that deposit collagen and extracellular matrix. Alpha-1 antitrypsin deficiency
causes emphysema through protease-antiprotease imbalance, not fibrosis, and this distractor
exploits the overlap in pulmonary pathophysiology concepts. The presence of fibroblastic
foci on histology is pathognomonic for TGF-β-mediated fibrogenesis.
Question 5 of 50
A 7-year-old boy presents with recurrent bacterial infections, particularly encapsulated
organisms. Flow cytometry reveals absent B lymphocytes. Genetic testing identifies a
mutation in the BTK gene. Which immunologic mechanism is primarily defective?
A. T-cell mediated cytotoxicity against intracellular pathogens
B. B-cell receptor signaling and maturation leading to antibody deficiency ✓ CORRECT
C. Complement-mediated opsonization of bacterial membranes
D. Toll-like receptor recognition of pathogen-associated molecular patterns
Correct Answer: B
Rationale: Bruton's tyrosine kinase (BTK) is essential for pre-B-cell receptor signaling and the
maturation of pro-B cells to mature B lymphocytes; its mutation causes X-linked
agammaglobulinemia characterized by absent circulating B cells and severe
hypogammaglobulinemia. T-cell cytotoxicity remains intact in this disorder, and this
distractor preys on the misconception that all adaptive immunity is compromised when only
the humoral arm is affected. The key clinical clue is the susceptibility to encapsulated
organisms, which requires opsonizing antibodies, and the absent B cells on flow cytometry.
Question 6 of 50
A 28-year-old woman develops facial flushing, urticaria, and bronchospasm within minutes of
eating shellfish. Her blood pressure drops to 82/48 mmHg. Which immunologic mechanism
underlies this acute systemic reaction?
A. Immune complex deposition activating complement and triggering neutrophil chemotaxis
B. T-cell mediated delayed hypersensitivity causing direct tissue cytotoxicity
C. Cytotoxic antibody binding to cellular antigens and inducing complement-mediated lysis
D. IgE-mediated mast cell degranulation releasing histamine and leukotrienes ✓ CORRECT
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 2-cm
hilar mass. Biopsy reveals small cell lung cancer. Molecular testing shows loss of
heterozygosity at chromosome 17p13.1. The tumor's uncontrolled proliferation is most
directly caused by which molecular mechanism?
A. Inactivation of the RB tumor suppressor gene leading to unregulated G1/S checkpoint
progression
B. Loss of p53-mediated DNA damage surveillance and apoptosis induction ✓ CORRECT
C. Constitutive activation of the RAS-MAPK signaling cascade driving continuous mitogenic
signals
D. Overexpression of telomerase preventing cellular senescence and enabling replicative
immortality
Correct Answer: B
Rationale: p53, encoded at 17p13.1, functions as the guardian of the genome by arresting the
cell cycle in response to DNA damage and initiating apoptosis when repair fails; loss of this
surveillance permits malignant cells with genomic instability to survive and proliferate. RB
inactivation is characteristic of small cell lung cancer but primarily governs G1/S transition
rather than DNA damage response, making it a tempting distractor because both are tumor
suppressors frequently implicated in lung cancer. On the exam, remember that chromosome
17p13.1 specifically localizes to p53, not RB, which resides on chromosome 13q14.
Question 2 of 50
A 24-year-old woman with a family history of breast cancer undergoes genetic counseling.
Her mother and maternal aunt both developed breast cancer before age 45. Genetic testing
,reveals a pathogenic variant in a gene responsible for homologous recombination repair.
Which cellular process is most directly impaired by this mutation?
A. Nucleotide excision repair of ultraviolet-induced thymine dimers
B. Base excision repair correcting oxidative damage to single bases
C. Mismatch repair correcting errors in DNA replication
D. Homologous recombination repair of double-strand DNA breaks ✓ CORRECT
Correct Answer: D
Rationale: BRCA1 and BRCA2 are tumor suppressor genes that mediate high-fidelity
homologous recombination repair of double-strand DNA breaks; loss of this function leads
to genomic instability and accumulation of mutations that drive carcinogenesis. Nucleotide
excision repair defects cause xeroderma pigmentosum, not hereditary breast cancer, and
students often confuse this because both are DNA repair mechanisms. The key exam clue is
the early-onset familial breast cancer pattern, which strongly suggests BRCA-related
homologous recombination deficiency rather than other repair pathway defects.
Question 3 of 50
A 62-year-old male with chronic hypertension has left ventricular hypertrophy on
echocardiogram. Myocardial biopsy demonstrates enlarged cardiac myocytes with increased
nuclear size but no increase in cell number. Which cellular adaptation is demonstrated?
A. Physiologic hypertrophy driven by increased synthesis of contractile proteins ✓ CORRECT
B. Pathologic hyperplasia resulting from growth factor-mediated myocyte proliferation
C. Metaplasia of cardiac myocytes into a more resistant fibroblast phenotype
D. Dysplasia characterized by disordered cellular architecture and nuclear pleomorphism
Correct Answer: A
Rationale: Cardiac myocytes are terminally differentiated cells incapable of mitosis, so
chronic pressure overload induces hypertrophy through increased protein synthesis and
sarcomere assembly rather than hyperplasia. Hyperplasia is incorrect because adult cardiac
myocytes do not divide, and this distractor targets the common misconception that
increased organ size always reflects increased cell number. Remember that hypertrophy
increases cell size while hyperplasia increases cell number, and cardiac tissue predominantly
hypertrophies in response to hemodynamic stress.
Question 4 of 50
A 45-year-old woman presents with progressive dyspnea and dry cough. High-resolution CT
shows honeycombing and traction bronchiectasis. Lung biopsy reveals fibroblastic foci and
excessive extracellular matrix deposition. Which molecular mechanism primarily drives this
pathologic tissue remodeling?
, A. Persistent activation of the PI3K-Akt pathway promoting cellular proliferation
B. Deficiency of alpha-1 antitrypsin leading to unopposed neutrophil elastase activity
C. Dysregulated TGF-β signaling stimulating fibroblast-to-myofibroblast differentiation ✓
CORRECT
D. Excessive VEGF production promoting abnormal angiogenesis within fibrotic lesions
Correct Answer: C
Rationale: Idiopathic pulmonary fibrosis is characterized by aberrant wound healing in which
TGF-β perpetually activates fibroblasts, driving their differentiation into contractile
myofibroblasts that deposit collagen and extracellular matrix. Alpha-1 antitrypsin deficiency
causes emphysema through protease-antiprotease imbalance, not fibrosis, and this distractor
exploits the overlap in pulmonary pathophysiology concepts. The presence of fibroblastic
foci on histology is pathognomonic for TGF-β-mediated fibrogenesis.
Question 5 of 50
A 7-year-old boy presents with recurrent bacterial infections, particularly encapsulated
organisms. Flow cytometry reveals absent B lymphocytes. Genetic testing identifies a
mutation in the BTK gene. Which immunologic mechanism is primarily defective?
A. T-cell mediated cytotoxicity against intracellular pathogens
B. B-cell receptor signaling and maturation leading to antibody deficiency ✓ CORRECT
C. Complement-mediated opsonization of bacterial membranes
D. Toll-like receptor recognition of pathogen-associated molecular patterns
Correct Answer: B
Rationale: Bruton's tyrosine kinase (BTK) is essential for pre-B-cell receptor signaling and the
maturation of pro-B cells to mature B lymphocytes; its mutation causes X-linked
agammaglobulinemia characterized by absent circulating B cells and severe
hypogammaglobulinemia. T-cell cytotoxicity remains intact in this disorder, and this
distractor preys on the misconception that all adaptive immunity is compromised when only
the humoral arm is affected. The key clinical clue is the susceptibility to encapsulated
organisms, which requires opsonizing antibodies, and the absent B cells on flow cytometry.
Question 6 of 50
A 28-year-old woman develops facial flushing, urticaria, and bronchospasm within minutes of
eating shellfish. Her blood pressure drops to 82/48 mmHg. Which immunologic mechanism
underlies this acute systemic reaction?
A. Immune complex deposition activating complement and triggering neutrophil chemotaxis
B. T-cell mediated delayed hypersensitivity causing direct tissue cytotoxicity
C. Cytotoxic antibody binding to cellular antigens and inducing complement-mediated lysis
D. IgE-mediated mast cell degranulation releasing histamine and leukotrienes ✓ CORRECT
