Midterm Actual Exam 2026/2027 – 100%
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Section 1: Cellular & Molecular Pathophysiology (Questions 1–8)
Q1: A 58-year-old patient with a 40-pack-year smoking history develops squamous cell carcinoma of the
lung. At the cellular level, which pathophysiologic process best explains the transformation of normal
bronchial epithelium to malignant cells?
A. Hypertrophy of normal cells in response to chronic irritation
B. Metaplasia of ciliated columnar cells to stratified squamous cells, followed by dysplasia and neoplasia
[CORRECT]
C. Hyperplasia of goblet cells leading to increased mucus production
D. Atrophy of alveolar cells due to chronic hypoxia
Correct Answer: B
Rationale: The best answer is B. Chronic irritation from cigarette smoke triggers metaplasia, where
normal ciliated columnar cells are replaced by more resilient stratified squamous cells—this adaptive
change becomes dysplastic over time with accumulated genetic mutations, eventually progressing to
invasive squamous cell carcinoma. This sequence illustrates the metaplasia-dysplasia-neoplasia pathway
that underlies many smoking-related malignancies.
Correct Answer: B
Q2: A patient who suffered a myocardial infarction 4 days ago develops ventricular wall rupture. Which
type of necrosis is most likely responsible for this complication?
A. Coagulative necrosis
B. Liquefactive necrosis
C. Caseous necrosis
D. Coagulative necrosis with enzymatic digestion leading to structural weakening [CORRECT]
Correct Answer: D
,Rationale: The best answer is D. Coagulative necrosis preserves tissue architecture initially, but by day
3–7 neutrophil infiltration brings proteolytic enzymes that digest the necrotic myocardium—this
enzymatic digestion weakens the ventricular wall and creates the window for rupture, which is why this
complication peaks around day 4–7 post-MI.
Correct Answer: D
Q3: A patient with chronic hepatitis C develops hepatocellular carcinoma. Which molecular mechanism
is most directly involved in the pathogenesis of virus-induced malignancy?
A. Direct viral invasion of hepatocytes causing immediate cell death
B. Chronic inflammation, oxidative stress, and integration of viral proteins disrupting cell cycle regulation
[CORRECT]
C. Viral-induced apoptosis of all infected hepatocytes
D. Acute viral replication causing massive hepatic necrosis
Correct Answer: B
Rationale: The best answer is B. Hepatitis C doesn't directly transform cells—instead, decades of chronic
inflammation generate reactive oxygen species that damage DNA, while viral proteins like core protein
and NS5A interfere with tumor suppressor pathways and promote cell survival. This inflammatory-
carcinogenic cascade explains why HCC develops 20–30 years after initial infection.
Correct Answer: B
Q4: A patient with a genetic mutation in the BRCA1 gene has an increased risk of breast and ovarian
cancer. Which cellular process is primarily disrupted by this mutation?
A. DNA repair via homologous recombination [CORRECT]
B. Cell membrane receptor signaling
C. Mitochondrial energy production
D. Protein synthesis at the ribosome
Correct Answer: A
Rationale: The best answer is A. BRCA1 is a tumor suppressor gene that encodes a protein essential for
repairing double-strand DNA breaks through homologous recombination—when this repair pathway
fails, cells accumulate mutations at an accelerated rate, dramatically increasing cancer susceptibility.
This is why BRCA1 mutation carriers have up to a 70% lifetime risk of breast cancer.
Correct Answer: A
Q5: During wound healing, a patient notices their surgical incision is red, warm, and slightly raised at day
5. Which phase of wound healing is most active at this time?
, A. Hemostasis
B. Inflammation
C. Proliferation [CORRECT]
D. Maturation
Correct Answer: C
Rationale: The best answer is C. By day 5, the wound has moved into the proliferative phase where
fibroblasts deposit collagen, granulation tissue forms, and angiogenesis creates new blood vessels—the
redness and warmth reflect this robust neovascularization and cellular activity, not active infection.
Hemostasis occurs within minutes, inflammation peaks at 24–48 hours, and maturation begins weeks
later.
Correct Answer: C
Q6: A patient with sickle cell disease experiences a vaso-occlusive crisis after exposure to cold weather.
Which pathophysiologic mechanism triggers the sickling of red blood cells?
A. Increased oxygen saturation causing hemoglobin polymerization
B. Deoxygenation of hemoglobin S leading to hydrophobic interactions and polymerization [CORRECT]
C. Increased plasma pH causing hemoglobin denaturation
D. Hyperhydration of red blood cells leading to membrane rupture
Correct Answer: B
Rationale: The best answer is B. Hemoglobin S polymerizes when deoxygenated because the valine
substitution at position 6 creates a hydrophobic pocket that interacts with complementary sites on
adjacent hemoglobin molecules—this polymerization distorts the red blood cell into the sickle shape,
causing hemolysis and vaso-occlusion. Cold exposure increases blood viscosity and peripheral
vasoconstriction, promoting deoxygenation and triggering the crisis.
Correct Answer: B
Q7: A patient with chronic granulomatous disease (CGD) develops recurrent severe infections with
catalase-positive organisms. Which pathophysiologic defect underlies this immunodeficiency?
A. Deficiency in antibody production by B lymphocytes
B. Defective NADPH oxidase in phagocytes preventing respiratory burst [CORRECT]
C. Absence of complement proteins C5–C9
D. Defective T-cell receptor signaling
Correct Answer: B
Rationale: The best answer is B. CGD results from mutations in the NADPH oxidase complex, which
generates the superoxide radical during the respiratory burst—without this oxidative killing mechanism,
phagocytes can ingest but cannot destroy catalase-positive organisms like Staphylococcus aureus,
Burkholderia cepacia, and Aspergillus species. Catalase-negative organisms are less problematic because