COMSAE Phase 1-Form ASA 105
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 67-year-old man with long-standing hypertension develops left
ventricular hypertrophy. Which cellular adaptation is most
responsible for the increase in myocardial wall thickness?
A. Hyperplasia
B. Metaplasia
C. Dysplasia
D. Hypertrophy
E. Atrophy
Rationale: Cardiac myocytes have limited ability to divide; therefore,
increased workload causes enlargement of existing cells (hypertrophy)
rather than hyperplasia. Hypertension increases afterload, stimulating
synthesis of contractile proteins and cellular enlargement.
2. A patient develops fever, tachycardia, and leukocytosis after
bacterial pneumonia. Which cytokine is most strongly associated
with induction of fever through hypothalamic prostaglandin
synthesis?
A. IL-4
B. IL-10
C. IL-1
,D. TGF-β
E. IL-5
Rationale: IL-1 is a major endogenous pyrogen. It stimulates
prostaglandin E2 production in the hypothalamus, resulting in
elevation of the thermoregulatory set point and fever.
3. A newborn exhibits cyanosis shortly after birth. Echocardiography
reveals transposition of the great arteries. Failure of migration of
which embryologic structure most likely caused this defect?
A. Neural tube
B. Endocardial cushions
C. Somites
D. Neural crest cells
E. Septum primum
Rationale: Neural crest cells contribute to formation of the
aorticopulmonary septum. Defective migration can result in
conotruncal abnormalities such as transposition of the great arteries,
truncus arteriosus, and tetralogy of Fallot.
4. Which enzyme catalyzes the rate-limiting step of glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Glucose-6-phosphatase
D. Lactate dehydrogenase
E. Phosphofructokinase-1
Rationale: Phosphofructokinase-1 converts fructose-6-phosphate to
fructose-1,6-bisphosphate and is the major regulatory enzyme of
glycolysis. It is activated by AMP and fructose-2,6-bisphosphate and
inhibited by ATP and citrate.
, 5. A patient with severe liver disease develops edema. Which plasma
protein deficiency is primarily responsible?
A. Fibrinogen
B. Ceruloplasmin
C. Transferrin
D. Albumin
E. Haptoglobin
Rationale: Albumin is the principal determinant of plasma oncotic
pressure. Reduced synthesis in liver disease lowers intravascular
oncotic pressure, promoting fluid movement into tissues.
6. During DNA replication, which enzyme synthesizes RNA primers?
A. DNA polymerase III
B. DNA ligase
C. Topoisomerase II
D. Helicase
E. Primase
Rationale: Primase generates short RNA primers that provide a free
3'-OH group necessary for DNA polymerases to initiate DNA synthesis.
7. A patient develops muscle weakness after administration of a
neuromuscular blocker that competitively inhibits acetylcholine
receptors. Which receptor type is affected?
A. Muscarinic M2
B. Muscarinic M3
C. GABA-A
D. Nicotinic Nm
E. α1 Adrenergic
, Rationale: Skeletal muscle neuromuscular junctions contain nicotinic
Nm receptors. Competitive antagonists such as rocuronium block
these receptors and prevent muscle contraction.
8. A woman with Graves disease has elevated thyroid hormone
levels. Which physiologic effect is expected?
A. Decreased basal metabolic rate
B. Bradycardia
C. Weight gain
D. Reduced oxygen consumption
E. Increased β-adrenergic receptor expression
Rationale: Thyroid hormone increases expression of β-adrenergic
receptors, producing heightened sensitivity to catecholamines and
symptoms such as tachycardia and tremor.
9. Which histologic feature is characteristic of skeletal muscle but
not smooth muscle?
A. Actin filaments
B. Myosin filaments
C. Calcium-mediated contraction
D. Sarcomeres
E. ATP utilization
Rationale: Skeletal muscle contains organized sarcomeres producing
striations. Smooth muscle lacks sarcomeres and instead contains
dense bodies.
10. A patient experiences an acute myocardial infarction. Four
hours later, which microscopic change is most likely present?
A. Fibrosis
B. Macrophage infiltration
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 67-year-old man with long-standing hypertension develops left
ventricular hypertrophy. Which cellular adaptation is most
responsible for the increase in myocardial wall thickness?
A. Hyperplasia
B. Metaplasia
C. Dysplasia
D. Hypertrophy
E. Atrophy
Rationale: Cardiac myocytes have limited ability to divide; therefore,
increased workload causes enlargement of existing cells (hypertrophy)
rather than hyperplasia. Hypertension increases afterload, stimulating
synthesis of contractile proteins and cellular enlargement.
2. A patient develops fever, tachycardia, and leukocytosis after
bacterial pneumonia. Which cytokine is most strongly associated
with induction of fever through hypothalamic prostaglandin
synthesis?
A. IL-4
B. IL-10
C. IL-1
,D. TGF-β
E. IL-5
Rationale: IL-1 is a major endogenous pyrogen. It stimulates
prostaglandin E2 production in the hypothalamus, resulting in
elevation of the thermoregulatory set point and fever.
3. A newborn exhibits cyanosis shortly after birth. Echocardiography
reveals transposition of the great arteries. Failure of migration of
which embryologic structure most likely caused this defect?
A. Neural tube
B. Endocardial cushions
C. Somites
D. Neural crest cells
E. Septum primum
Rationale: Neural crest cells contribute to formation of the
aorticopulmonary septum. Defective migration can result in
conotruncal abnormalities such as transposition of the great arteries,
truncus arteriosus, and tetralogy of Fallot.
4. Which enzyme catalyzes the rate-limiting step of glycolysis?
A. Hexokinase
B. Pyruvate kinase
C. Glucose-6-phosphatase
D. Lactate dehydrogenase
E. Phosphofructokinase-1
Rationale: Phosphofructokinase-1 converts fructose-6-phosphate to
fructose-1,6-bisphosphate and is the major regulatory enzyme of
glycolysis. It is activated by AMP and fructose-2,6-bisphosphate and
inhibited by ATP and citrate.
, 5. A patient with severe liver disease develops edema. Which plasma
protein deficiency is primarily responsible?
A. Fibrinogen
B. Ceruloplasmin
C. Transferrin
D. Albumin
E. Haptoglobin
Rationale: Albumin is the principal determinant of plasma oncotic
pressure. Reduced synthesis in liver disease lowers intravascular
oncotic pressure, promoting fluid movement into tissues.
6. During DNA replication, which enzyme synthesizes RNA primers?
A. DNA polymerase III
B. DNA ligase
C. Topoisomerase II
D. Helicase
E. Primase
Rationale: Primase generates short RNA primers that provide a free
3'-OH group necessary for DNA polymerases to initiate DNA synthesis.
7. A patient develops muscle weakness after administration of a
neuromuscular blocker that competitively inhibits acetylcholine
receptors. Which receptor type is affected?
A. Muscarinic M2
B. Muscarinic M3
C. GABA-A
D. Nicotinic Nm
E. α1 Adrenergic
, Rationale: Skeletal muscle neuromuscular junctions contain nicotinic
Nm receptors. Competitive antagonists such as rocuronium block
these receptors and prevent muscle contraction.
8. A woman with Graves disease has elevated thyroid hormone
levels. Which physiologic effect is expected?
A. Decreased basal metabolic rate
B. Bradycardia
C. Weight gain
D. Reduced oxygen consumption
E. Increased β-adrenergic receptor expression
Rationale: Thyroid hormone increases expression of β-adrenergic
receptors, producing heightened sensitivity to catecholamines and
symptoms such as tachycardia and tremor.
9. Which histologic feature is characteristic of skeletal muscle but
not smooth muscle?
A. Actin filaments
B. Myosin filaments
C. Calcium-mediated contraction
D. Sarcomeres
E. ATP utilization
Rationale: Skeletal muscle contains organized sarcomeres producing
striations. Smooth muscle lacks sarcomeres and instead contains
dense bodies.
10. A patient experiences an acute myocardial infarction. Four
hours later, which microscopic change is most likely present?
A. Fibrosis
B. Macrophage infiltration
