COMSAE Phase 1 Form ASA 110
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 24-year-old woman develops severe fatigue and pallor.
Laboratory studies reveal a hemoglobin concentration of 7.8 g/dL
and an MCV of 68 fL. Bone marrow examination demonstrates
erythroid hyperplasia. Which physiologic mechanism is most likely
responsible for the marrow finding?
A. Increased erythropoietin production by the kidneys
B. Increased thrombopoietin secretion by the liver
C. Increased IL-1 production by macrophages
D. Increased hepcidin synthesis by hepatocytes
E. Increased calcitonin release from parafollicular cells
Answer: A. Increased erythropoietin production by the kidneys
Rationale: Tissue hypoxia stimulates renal peritubular interstitial cells
to produce erythropoietin, which increases erythroid precursor
proliferation in bone marrow. This compensatory response explains
erythroid hyperplasia in anemia.
2. A researcher blocks the conversion of phosphoenolpyruvate to
pyruvate. Which enzyme has been inhibited?
A. Hexokinase
B. Pyruvate kinase
,C. Phosphofructokinase-1
D. Lactate dehydrogenase
E. Enolase
Answer: B. Pyruvate kinase
Rationale: Pyruvate kinase catalyzes the final irreversible step of
glycolysis, converting phosphoenolpyruvate into pyruvate with
generation of ATP.
3. A patient develops nephrotic syndrome due to minimal change
disease. Which glomerular structure is primarily damaged?
A. Mesangial matrix
B. Endothelial fenestrations
C. Podocyte foot processes
D. Bowman capsule
E. Juxtaglomerular apparatus
Answer: C. Podocyte foot processes
Rationale: Minimal change disease is characterized by diffuse
effacement of podocyte foot processes, resulting in selective
albuminuria.
4. A 65-year-old smoker develops squamous cell carcinoma of the
lung. Which genetic abnormality is most commonly associated
with this malignancy?
A. EGFR mutation
B. ALK rearrangement
C. RB gene inactivation
D. APC mutation
E. VHL mutation
Answer: C. RB gene inactivation
,Rationale: Squamous cell carcinoma frequently demonstrates loss of
tumor suppressor genes including RB and TP53.
5. A patient with myasthenia gravis receives pyridostigmine. The
therapeutic effect results from inhibition of which enzyme?
A. Monoamine oxidase
B. Acetylcholinesterase
C. Catechol-O-methyltransferase
D. Adenylate cyclase
E. Phospholipase C
Answer: B. Acetylcholinesterase
Rationale: Pyridostigmine increases acetylcholine concentrations at
the neuromuscular junction by inhibiting acetylcholinesterase.
6. Which immunoglobulin is most effective at crossing the placenta?
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM
Answer: D. IgG
Rationale: IgG is actively transported across the placenta via Fc
receptors and provides passive neonatal immunity.
7. A patient experiences loss of pain and temperature sensation on
the right side of the body below T10 after a spinal cord lesion.
Which tract is damaged?
A. Dorsal columns
B. Corticospinal tract
C. Spinothalamic tract
, D. Spinocerebellar tract
E. Vestibulospinal tract
Answer: C. Spinothalamic tract
Rationale: The spinothalamic tract carries pain and temperature
sensation and crosses shortly after entering the spinal cord.
8. During prolonged fasting, which organ becomes the major
producer of glucose through gluconeogenesis?
A. Brain
B. Skeletal muscle
C. Liver
D. Pancreas
E. Spleen
Answer: C. Liver
Rationale: The liver is the primary gluconeogenic organ during fasting,
with the kidney contributing during prolonged starvation.
9. A child develops recurrent infections with catalase-positive
organisms. Which enzyme deficiency is most likely present?
A. Myeloperoxidase
B. NADPH oxidase
C. Superoxide dismutase
D. Catalase
E. Lysozyme
Answer: B. NADPH oxidase
Rationale: Chronic granulomatous disease results from NADPH
oxidase deficiency, impairing respiratory burst activity.
10. Which cranial nerve innervates the lateral rectus muscle?
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 24-year-old woman develops severe fatigue and pallor.
Laboratory studies reveal a hemoglobin concentration of 7.8 g/dL
and an MCV of 68 fL. Bone marrow examination demonstrates
erythroid hyperplasia. Which physiologic mechanism is most likely
responsible for the marrow finding?
A. Increased erythropoietin production by the kidneys
B. Increased thrombopoietin secretion by the liver
C. Increased IL-1 production by macrophages
D. Increased hepcidin synthesis by hepatocytes
E. Increased calcitonin release from parafollicular cells
Answer: A. Increased erythropoietin production by the kidneys
Rationale: Tissue hypoxia stimulates renal peritubular interstitial cells
to produce erythropoietin, which increases erythroid precursor
proliferation in bone marrow. This compensatory response explains
erythroid hyperplasia in anemia.
2. A researcher blocks the conversion of phosphoenolpyruvate to
pyruvate. Which enzyme has been inhibited?
A. Hexokinase
B. Pyruvate kinase
,C. Phosphofructokinase-1
D. Lactate dehydrogenase
E. Enolase
Answer: B. Pyruvate kinase
Rationale: Pyruvate kinase catalyzes the final irreversible step of
glycolysis, converting phosphoenolpyruvate into pyruvate with
generation of ATP.
3. A patient develops nephrotic syndrome due to minimal change
disease. Which glomerular structure is primarily damaged?
A. Mesangial matrix
B. Endothelial fenestrations
C. Podocyte foot processes
D. Bowman capsule
E. Juxtaglomerular apparatus
Answer: C. Podocyte foot processes
Rationale: Minimal change disease is characterized by diffuse
effacement of podocyte foot processes, resulting in selective
albuminuria.
4. A 65-year-old smoker develops squamous cell carcinoma of the
lung. Which genetic abnormality is most commonly associated
with this malignancy?
A. EGFR mutation
B. ALK rearrangement
C. RB gene inactivation
D. APC mutation
E. VHL mutation
Answer: C. RB gene inactivation
,Rationale: Squamous cell carcinoma frequently demonstrates loss of
tumor suppressor genes including RB and TP53.
5. A patient with myasthenia gravis receives pyridostigmine. The
therapeutic effect results from inhibition of which enzyme?
A. Monoamine oxidase
B. Acetylcholinesterase
C. Catechol-O-methyltransferase
D. Adenylate cyclase
E. Phospholipase C
Answer: B. Acetylcholinesterase
Rationale: Pyridostigmine increases acetylcholine concentrations at
the neuromuscular junction by inhibiting acetylcholinesterase.
6. Which immunoglobulin is most effective at crossing the placenta?
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM
Answer: D. IgG
Rationale: IgG is actively transported across the placenta via Fc
receptors and provides passive neonatal immunity.
7. A patient experiences loss of pain and temperature sensation on
the right side of the body below T10 after a spinal cord lesion.
Which tract is damaged?
A. Dorsal columns
B. Corticospinal tract
C. Spinothalamic tract
, D. Spinocerebellar tract
E. Vestibulospinal tract
Answer: C. Spinothalamic tract
Rationale: The spinothalamic tract carries pain and temperature
sensation and crosses shortly after entering the spinal cord.
8. During prolonged fasting, which organ becomes the major
producer of glucose through gluconeogenesis?
A. Brain
B. Skeletal muscle
C. Liver
D. Pancreas
E. Spleen
Answer: C. Liver
Rationale: The liver is the primary gluconeogenic organ during fasting,
with the kidney contributing during prolonged starvation.
9. A child develops recurrent infections with catalase-positive
organisms. Which enzyme deficiency is most likely present?
A. Myeloperoxidase
B. NADPH oxidase
C. Superoxide dismutase
D. Catalase
E. Lysozyme
Answer: B. NADPH oxidase
Rationale: Chronic granulomatous disease results from NADPH
oxidase deficiency, impairing respiratory burst activity.
10. Which cranial nerve innervates the lateral rectus muscle?
