11 Question Bank (Latest 2026/2027 Edition) –
Questions, Answers & Detailed Rationales
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SECTION 1: CELLULAR PATHOPHYSIOLOGY AND GENETIC DISORDERS
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Question 1
A 45-year-old male with a history of chronic alcohol use presents with numbness and
tingling in his extremities. Laboratory studies reveal elevated homocysteine and
methylmalonic acid levels. Which vitamin deficiency is most likely responsible for these
laboratory findings?
A. Folate deficiency
B. Vitamin B12 (cobalamin) deficiency
C. Vitamin B6 (pyridoxine) deficiency
D. Vitamin C deficiency
Correct Answer:
B — Vitamin B12 (cobalamin) deficiency
Rationale:
Vitamin B12 deficiency impairs both the conversion of homocysteine to methionine and
methylmalonyl-CoA to succinyl-CoA, causing elevation of both homocysteine and
methylmalonic acid. Folate deficiency only elevates homocysteine without affecting
methylmalonic acid levels, making it the strongest distractor.
Question 2
,A 6-year-old child presents with recurrent infections, failure to thrive, and developmental
delay. Genetic testing reveals a mutation in the CFTR gene. Which pathophysiological
mechanism best explains the thick, inspissated secretions characteristic of this
disorder?
A. Defective chloride ion transport leading to decreased luminal water content
B. Excessive sodium absorption causing hyperosmolar secretions
C. Impaired ciliary function resulting in mucus accumulation
D. Increased mucus gland secretion due to autonomic dysfunction
Correct Answer:
A — Defective chloride ion transport leading to decreased luminal water content
Rationale:
The CFTR gene encodes a chloride channel; defective function reduces chloride and
water secretion into the lumen, leading to dehydrated, viscous mucus. While sodium
absorption is also affected, the primary defect is chloride transport dysfunction, not
excessive sodium absorption.
Question 3
A patient undergoing chemotherapy develops tumor lysis syndrome. Which electrolyte
imbalance poses the greatest immediate risk for cardiac arrest?
A. Hypernatremia
B. Hyperkalemia
C. Hypercalcemia
D. Hypomagnesemia
Correct Answer:
B — Hyperkalemia
Rationale:
,Tumor lysis syndrome releases intracellular potassium, causing hyperkalemia that can
precipitate fatal ventricular arrhythmias. While hyperphosphatemia and hypocalcemia
also occur, hyperkalemia presents the most acute life-threatening cardiac risk requiring
immediate intervention.
Question 4
A 28-year-old female presents with jaundice, dark urine, and fatigue. Laboratory studies
show elevated unconjugated bilirubin with normal liver enzymes. Peripheral blood
smear reveals spherocytes. Which pathophysiological mechanism is most likely
responsible?
A. Defective hepatocyte uptake of bilirubin
B. Impaired conjugation of bilirubin due to glucuronyl transferase deficiency
C. Increased red blood cell destruction exceeding hepatic processing capacity
D. Biliary obstruction preventing bilirubin excretion
Correct Answer:
C — Increased red blood cell destruction exceeding hepatic processing capacity
Rationale:
The presence of spherocytes and elevated unconjugated bilirubin with normal liver
enzymes indicates hemolytic anemia, where RBC destruction overwhelms the liver's
conjugation capacity. Hereditary spherocytosis or autoimmune hemolysis would
present this pattern, distinguishing it from hepatocellular or obstructive jaundice.
Question 5
A patient with type 2 diabetes mellitus develops nonketotic hyperosmolar
hyperglycemia. Which pathophysiological difference from diabetic ketoacidosis best
explains the absence of ketosis in this condition?
A. Absence of insulin deficiency
, B. Presence of sufficient insulin to suppress lipolysis
C. Normal glucagon secretion preventing ketogenesis
D. Adequate fluid intake diluting ketone bodies
Correct Answer:
B — Presence of sufficient insulin to suppress lipolysis
Rationale:
In NKHH, residual insulin levels are sufficient to suppress adipose tissue lipolysis and
hepatic ketogenesis, unlike DKA where absolute insulin deficiency promotes free fatty
acid oxidation and ketone production. Both conditions involve hyperglycemia and
dehydration, but the relative insulin preservation distinguishes them.
Question 6
A 55-year-old male with a 30-pack-year smoking history presents with a chronic cough
and hemoptysis. CT scan reveals a central lung mass. Biopsy demonstrates small, dark
blue cells with scant cytoplasm and nuclear molding. Which chromosomal abnormality
is most commonly associated with this malignancy?
A. t(9;22) Philadelphia chromosome
B. Deletion of chromosome 3p (3p21-23)
C. t(11;14) translocation
D. Deletion of the long arm of chromosome 5 (5q-)
Correct Answer:
B — Deletion of chromosome 3p (3p21-23)
Rationale:
Small cell lung carcinoma (SCLC) is characterized by deletion of 3p involving the tumor
suppressor gene region, along with mutations in TP53 and RB1. The t(9;22) is
associated with CML, t(11;14) with mantle cell lymphoma, and 5q- with myelodysplastic
syndromes.