COMSAE Phase 1 – Form 108: Premium
Study Companion | Master Practice
Questions, Annotated Answer Keys, and
Expert Rationales (PDF)
1. A 45-year-old male presents with fatigue and jaundice.
Labs reveal elevated unconjugated bilirubin, normal liver
enzymes, and no evidence of hemolysis. Which of the
following is the most likely diagnosis?
A) Dubin-Johnson syndrome
B) Gilbert syndrome
C) Crigler-Najjar syndrome type I
D) Rotor syndrome
Rationale: Gilbert syndrome is a common, benign condition
characterized by a mild decrease in UDP-
glucuronosyltransferase activity, leading to isolated
unconjugated hyperbilirubinemia often precipitated by stress
or fasting.
2. Which vitamin deficiency is classically associated with
glossitis, cheilosis, and corneal vascularization?
A) Thiamine (B1)
B) Niacin (B3)
,C) Riboflavin (B2)
D) Pyridoxine (B6)
Rationale: Riboflavin is a precursor to FAD and FMN; its
deficiency leads to the "2 Cs" (cheilosis, corneal
vascularization) and glossitis.
3. In a patient with primary hyperparathyroidism, which of
the following serum patterns is most expected?
A) High Calcium, Low Phosphate, High PTH
B) Low Calcium, High Phosphate, High PTH
C) High Calcium, Low Phosphate, High PTH
D) High Calcium, High Phosphate, Low PTH
Rationale: Excess PTH increases bone resorption and renal
calcium reabsorption while promoting phosphate excretion in
the proximal tubule.
4. Which of the following is the rate-limiting enzyme in
cholesterol synthesis?
A) Acyl-CoA cholesterol acyltransferase
B) HMG-CoA reductase
C) Mevalonate kinase
D) Citrate synthase
Rationale: HMG-CoA reductase converts HMG-CoA to
mevalonate and is the primary target for statin therapy.
,5. A patient with a history of chronic alcohol use presents
with ataxia and confusion. Which anatomical structure is
most likely affected?
A) Mamillary bodies
B) Hippocampus
C) Substantia nigra
D) Dentate nucleus
Rationale: Wernicke-Korsakoff syndrome, caused by thiamine
deficiency, classically involves the mamillary bodies and
medial dorsal nucleus of the thalamus.
6. Which mechanism describes the action of
aminoglycosides?
A) Inhibition of cell wall synthesis
B) Irreversible inhibition of 30S ribosomal subunit
C) Inhibition of DNA gyrase
D) Inhibition of folic acid synthesis
Rationale: Aminoglycosides bind the 30S subunit, preventing
the formation of the initiation complex and causing
misreading of mRNA.
7. Which phase of the cardiac cycle is characterized by all
four valves being closed and ventricular pressure rising?
A) Atrial systole
B) Rapid ventricular filling
C) Isovolumetric contraction
, D) Ventricular ejection
Rationale: During isovolumetric contraction, the ventricles
contract against closed AV and semilunar valves, leading to a
sharp rise in pressure without volume change.
8. A patient with systemic lupus erythematosus (SLE) is at
highest risk for which type of glomerular disease?
A) Minimal change disease
B) Focal segmental glomerulosclerosis
C) Diffuse proliferative glomerulonephritis
D) Membranous nephropathy
Rationale: Diffuse proliferative GN is the most common and
severe form of renal involvement in SLE, often presenting with
"wire-loop" capillary appearance on histology.
9. Which hormone stimulates the release of bicarbonate
from the pancreas?
A) Gastrin
B) Cholecystokinin (CCK)
C) Secretin
D) Somatostatin
Rationale: Secretin is released by S cells of the duodenum in
response to acid; it stimulates the pancreas to secrete
bicarbonate-rich fluid to neutralize chime.
10. A mutation in the FBN1 gene is associated with which
connective tissue disorder?
Study Companion | Master Practice
Questions, Annotated Answer Keys, and
Expert Rationales (PDF)
1. A 45-year-old male presents with fatigue and jaundice.
Labs reveal elevated unconjugated bilirubin, normal liver
enzymes, and no evidence of hemolysis. Which of the
following is the most likely diagnosis?
A) Dubin-Johnson syndrome
B) Gilbert syndrome
C) Crigler-Najjar syndrome type I
D) Rotor syndrome
Rationale: Gilbert syndrome is a common, benign condition
characterized by a mild decrease in UDP-
glucuronosyltransferase activity, leading to isolated
unconjugated hyperbilirubinemia often precipitated by stress
or fasting.
2. Which vitamin deficiency is classically associated with
glossitis, cheilosis, and corneal vascularization?
A) Thiamine (B1)
B) Niacin (B3)
,C) Riboflavin (B2)
D) Pyridoxine (B6)
Rationale: Riboflavin is a precursor to FAD and FMN; its
deficiency leads to the "2 Cs" (cheilosis, corneal
vascularization) and glossitis.
3. In a patient with primary hyperparathyroidism, which of
the following serum patterns is most expected?
A) High Calcium, Low Phosphate, High PTH
B) Low Calcium, High Phosphate, High PTH
C) High Calcium, Low Phosphate, High PTH
D) High Calcium, High Phosphate, Low PTH
Rationale: Excess PTH increases bone resorption and renal
calcium reabsorption while promoting phosphate excretion in
the proximal tubule.
4. Which of the following is the rate-limiting enzyme in
cholesterol synthesis?
A) Acyl-CoA cholesterol acyltransferase
B) HMG-CoA reductase
C) Mevalonate kinase
D) Citrate synthase
Rationale: HMG-CoA reductase converts HMG-CoA to
mevalonate and is the primary target for statin therapy.
,5. A patient with a history of chronic alcohol use presents
with ataxia and confusion. Which anatomical structure is
most likely affected?
A) Mamillary bodies
B) Hippocampus
C) Substantia nigra
D) Dentate nucleus
Rationale: Wernicke-Korsakoff syndrome, caused by thiamine
deficiency, classically involves the mamillary bodies and
medial dorsal nucleus of the thalamus.
6. Which mechanism describes the action of
aminoglycosides?
A) Inhibition of cell wall synthesis
B) Irreversible inhibition of 30S ribosomal subunit
C) Inhibition of DNA gyrase
D) Inhibition of folic acid synthesis
Rationale: Aminoglycosides bind the 30S subunit, preventing
the formation of the initiation complex and causing
misreading of mRNA.
7. Which phase of the cardiac cycle is characterized by all
four valves being closed and ventricular pressure rising?
A) Atrial systole
B) Rapid ventricular filling
C) Isovolumetric contraction
, D) Ventricular ejection
Rationale: During isovolumetric contraction, the ventricles
contract against closed AV and semilunar valves, leading to a
sharp rise in pressure without volume change.
8. A patient with systemic lupus erythematosus (SLE) is at
highest risk for which type of glomerular disease?
A) Minimal change disease
B) Focal segmental glomerulosclerosis
C) Diffuse proliferative glomerulonephritis
D) Membranous nephropathy
Rationale: Diffuse proliferative GN is the most common and
severe form of renal involvement in SLE, often presenting with
"wire-loop" capillary appearance on histology.
9. Which hormone stimulates the release of bicarbonate
from the pancreas?
A) Gastrin
B) Cholecystokinin (CCK)
C) Secretin
D) Somatostatin
Rationale: Secretin is released by S cells of the duodenum in
response to acid; it stimulates the pancreas to secrete
bicarbonate-rich fluid to neutralize chime.
10. A mutation in the FBN1 gene is associated with which
connective tissue disorder?
