NR 507 Midterm Exam Advanced
Pathophysiology 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 62-year-old male with a 40 pack-year smoking history presents with progressive dyspnea
and a chronic productive cough. His pulmonary function tests show an FEV1/FVC ratio of
0.58. Bronchial biopsy reveals enlarged alveolar macrophages with abundant, undigested
material in phagolysosomes. Which intracellular degradative pathway is most likely impaired
in this patient's airway epithelial cells?
A. Chaperone-mediated autophagy involving Hsc70 and LAMP-2A translocation
B. Macroautophagy involving LC3-II conjugation and autophagosome-lysosome fusion ✓
CORRECT
C. The ubiquitin-proteasome system responsible for tagging short-lived regulatory proteins
D. Microautophagy characterized by direct lysosomal membrane invagination
Correct Answer: B
Rationale: Cigarette smoke induces oxidative stress and protein aggregation that
overwhelms macroautophagy, leading to defective LC3-II mediated autophagosome
formation and impaired lysosomal degradation in alveolar macrophages. Option A is
tempting because chaperone-mediated autophagy also declines with age, but it selectively
degrades cytosolic proteins with KFERQ-like motifs and is not the primary pathway
responsible for clearing damaged organelles and protein aggregates in smoke-exposed
airway cells. Recognizing that emphysema involves autophagic cell death helps distinguish
macroautophagy as the central defective mechanism.
Question 2 of 50
A 28-year-old female is diagnosed with Li-Fraumeni syndrome after her mother and sister
both developed premenopausal breast cancer. Genetic testing reveals a germline mutation in
,TP53. During a routine cell cycle review, she asks which checkpoint is most critically
compromised by this inherited defect. Which molecular event best explains the
pathophysiologic consequence of mutant p53 in her cells?
A. Unrestrained activation of cyclin D-CDK4/6 complexes driving G1/S transition despite DNA
damage
B. Persistent activation of ATM kinase leading to excessive double-strand break repair
C. Inability to phosphorylate Rb protein, resulting in permanent cell cycle arrest in G0 phase
D. Failure to transcriptionally induce p21, preventing G1 arrest and permitting replication of
damaged DNA ✓ CORRECT
Correct Answer: D
Rationale: Wild-type p53 functions as the "guardian of the genome" by transactivating p21 in
response to DNA damage, inducing G1 cell cycle arrest; loss of this function allows damaged
DNA to proceed into S phase. Option C misidentifies the mechanism because p53 does not
directly phosphorylate Rb; rather, p21 inhibits CDKs that phosphorylate Rb, and mutant p53
loses this indirect control. On the exam, remember that p53 acts primarily through
p21-mediated CDK inhibition at the G1/S checkpoint, not through direct Rb phosphorylation.
Question 3 of 50
A 45-year-old male with chronic alcohol use disorder presents with jaundice, ascites, and
palmar erythema. Liver biopsy shows hepatocyte swelling, Mallory-Denk bodies, and
extensive fatty change. The pathologist notes that the endoplasmic reticulum appears dilated
and ribosomes are detached. Which cellular adaptation or response best accounts for these
ultrastructural findings?
A. An accumulation of misfolded proteins triggering the unfolded protein response and ER
stress ✓ CORRECT
B. Activation of peroxisome proliferator-activated receptors stimulating mitochondrial
biogenesis
C. Hypertrophy of the smooth endoplasmic reticulum due to cytochrome P450 enzyme
induction
D. Metaplasia of hepatocytes into bile duct epithelium as a protective adaptation
Correct Answer: A
Rationale: Chronic alcohol metabolism generates acetaldehyde and reactive oxygen species
that cause protein misfolding, triggering the unfolded protein response with BiP/GRP78
activation, ER dilation, and ribosomal detachment. Option C describes a real
phenomenon—CYP2E1 induction does cause SER proliferation—but that produces a different
ultrastructural picture and does not explain the Mallory-Denk bodies or ribosomal
detachment seen here. In alcoholic liver disease, ER stress-mediated apoptosis is a key
driver of hepatocyte injury, distinguishing it from simple enzyme induction.
, Question 4 of 50
A 7-year-old boy presents with recurrent sinopulmonary infections, poor growth, and
steatorrhea. Sweat chloride testing reveals a value of 68 mEq/L. His parents are
asymptomatic carriers. Which pattern of Mendelian inheritance and underlying molecular
defect best explains this family's disease?
A. Autosomal dominant inheritance with a gain-of-function mutation in the CFTR chloride
channel
B. X-linked recessive inheritance with absent dystrophin expression in respiratory muscle
C. Autosomal recessive inheritance with defective CFTR protein folding and premature
degradation at the ER-Golgi interface ✓ CORRECT
D. Mitochondrial inheritance with defective oxidative phosphorylation in pancreatic acinar
cells
Correct Answer: C
Rationale: Cystic fibrosis follows autosomal recessive inheritance, and the most common
mutation ΔF508 causes CFTR misfolding that is retained in the ER and targeted for
proteasomal degradation, preventing apical membrane localization. Option A incorrectly
assigns dominant inheritance and gain-of-function to CFTR, when in fact CFTR mutations are
loss-of-function alleles with recessive transmission. Remember that ΔF508 specifically
impairs protein processing rather than channel gating, which is why correctors like
lumacaftor aim to restore trafficking.
Question 5 of 50
A 55-year-old female with estrogen receptor-positive breast cancer is started on tamoxifen.
Tumor genomic profiling reveals amplification of the HER2/neu gene. Which signal
transduction mechanism best explains how HER2 overexpression promotes tumor cell
survival and proliferation independent of ligand binding?
A. Sequestration of estrogen receptor alpha in the cytoplasm, preventing nuclear
translocation
B. Constitutive dimerization and activation of intrinsic tyrosine kinase activity leading to
downstream PI3K/AKT and MAPK signaling ✓ CORRECT
C. Persistent inhibition of the mTOR pathway leading to autophagy-dependent tumor cell
death
D. Activation of G-protein coupled estrogen receptor signaling via membrane-associated
GPER1
Correct Answer: B
Rationale: HER2/neu is a receptor tyrosine kinase that lacks a known ligand; gene
amplification drives spontaneous homo- and heterodimerization, autophosphorylation, and
constitutive activation of PI3K/AKT and Ras/MAPK survival pathways. Option A confuses
Pathophysiology 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 62-year-old male with a 40 pack-year smoking history presents with progressive dyspnea
and a chronic productive cough. His pulmonary function tests show an FEV1/FVC ratio of
0.58. Bronchial biopsy reveals enlarged alveolar macrophages with abundant, undigested
material in phagolysosomes. Which intracellular degradative pathway is most likely impaired
in this patient's airway epithelial cells?
A. Chaperone-mediated autophagy involving Hsc70 and LAMP-2A translocation
B. Macroautophagy involving LC3-II conjugation and autophagosome-lysosome fusion ✓
CORRECT
C. The ubiquitin-proteasome system responsible for tagging short-lived regulatory proteins
D. Microautophagy characterized by direct lysosomal membrane invagination
Correct Answer: B
Rationale: Cigarette smoke induces oxidative stress and protein aggregation that
overwhelms macroautophagy, leading to defective LC3-II mediated autophagosome
formation and impaired lysosomal degradation in alveolar macrophages. Option A is
tempting because chaperone-mediated autophagy also declines with age, but it selectively
degrades cytosolic proteins with KFERQ-like motifs and is not the primary pathway
responsible for clearing damaged organelles and protein aggregates in smoke-exposed
airway cells. Recognizing that emphysema involves autophagic cell death helps distinguish
macroautophagy as the central defective mechanism.
Question 2 of 50
A 28-year-old female is diagnosed with Li-Fraumeni syndrome after her mother and sister
both developed premenopausal breast cancer. Genetic testing reveals a germline mutation in
,TP53. During a routine cell cycle review, she asks which checkpoint is most critically
compromised by this inherited defect. Which molecular event best explains the
pathophysiologic consequence of mutant p53 in her cells?
A. Unrestrained activation of cyclin D-CDK4/6 complexes driving G1/S transition despite DNA
damage
B. Persistent activation of ATM kinase leading to excessive double-strand break repair
C. Inability to phosphorylate Rb protein, resulting in permanent cell cycle arrest in G0 phase
D. Failure to transcriptionally induce p21, preventing G1 arrest and permitting replication of
damaged DNA ✓ CORRECT
Correct Answer: D
Rationale: Wild-type p53 functions as the "guardian of the genome" by transactivating p21 in
response to DNA damage, inducing G1 cell cycle arrest; loss of this function allows damaged
DNA to proceed into S phase. Option C misidentifies the mechanism because p53 does not
directly phosphorylate Rb; rather, p21 inhibits CDKs that phosphorylate Rb, and mutant p53
loses this indirect control. On the exam, remember that p53 acts primarily through
p21-mediated CDK inhibition at the G1/S checkpoint, not through direct Rb phosphorylation.
Question 3 of 50
A 45-year-old male with chronic alcohol use disorder presents with jaundice, ascites, and
palmar erythema. Liver biopsy shows hepatocyte swelling, Mallory-Denk bodies, and
extensive fatty change. The pathologist notes that the endoplasmic reticulum appears dilated
and ribosomes are detached. Which cellular adaptation or response best accounts for these
ultrastructural findings?
A. An accumulation of misfolded proteins triggering the unfolded protein response and ER
stress ✓ CORRECT
B. Activation of peroxisome proliferator-activated receptors stimulating mitochondrial
biogenesis
C. Hypertrophy of the smooth endoplasmic reticulum due to cytochrome P450 enzyme
induction
D. Metaplasia of hepatocytes into bile duct epithelium as a protective adaptation
Correct Answer: A
Rationale: Chronic alcohol metabolism generates acetaldehyde and reactive oxygen species
that cause protein misfolding, triggering the unfolded protein response with BiP/GRP78
activation, ER dilation, and ribosomal detachment. Option C describes a real
phenomenon—CYP2E1 induction does cause SER proliferation—but that produces a different
ultrastructural picture and does not explain the Mallory-Denk bodies or ribosomal
detachment seen here. In alcoholic liver disease, ER stress-mediated apoptosis is a key
driver of hepatocyte injury, distinguishing it from simple enzyme induction.
, Question 4 of 50
A 7-year-old boy presents with recurrent sinopulmonary infections, poor growth, and
steatorrhea. Sweat chloride testing reveals a value of 68 mEq/L. His parents are
asymptomatic carriers. Which pattern of Mendelian inheritance and underlying molecular
defect best explains this family's disease?
A. Autosomal dominant inheritance with a gain-of-function mutation in the CFTR chloride
channel
B. X-linked recessive inheritance with absent dystrophin expression in respiratory muscle
C. Autosomal recessive inheritance with defective CFTR protein folding and premature
degradation at the ER-Golgi interface ✓ CORRECT
D. Mitochondrial inheritance with defective oxidative phosphorylation in pancreatic acinar
cells
Correct Answer: C
Rationale: Cystic fibrosis follows autosomal recessive inheritance, and the most common
mutation ΔF508 causes CFTR misfolding that is retained in the ER and targeted for
proteasomal degradation, preventing apical membrane localization. Option A incorrectly
assigns dominant inheritance and gain-of-function to CFTR, when in fact CFTR mutations are
loss-of-function alleles with recessive transmission. Remember that ΔF508 specifically
impairs protein processing rather than channel gating, which is why correctors like
lumacaftor aim to restore trafficking.
Question 5 of 50
A 55-year-old female with estrogen receptor-positive breast cancer is started on tamoxifen.
Tumor genomic profiling reveals amplification of the HER2/neu gene. Which signal
transduction mechanism best explains how HER2 overexpression promotes tumor cell
survival and proliferation independent of ligand binding?
A. Sequestration of estrogen receptor alpha in the cytoplasm, preventing nuclear
translocation
B. Constitutive dimerization and activation of intrinsic tyrosine kinase activity leading to
downstream PI3K/AKT and MAPK signaling ✓ CORRECT
C. Persistent inhibition of the mTOR pathway leading to autophagy-dependent tumor cell
death
D. Activation of G-protein coupled estrogen receptor signaling via membrane-associated
GPER1
Correct Answer: B
Rationale: HER2/neu is a receptor tyrosine kinase that lacks a known ligand; gene
amplification drives spontaneous homo- and heterodimerization, autophosphorylation, and
constitutive activation of PI3K/AKT and Ras/MAPK survival pathways. Option A confuses
