COMSAE Phase 1 Form ASA 106
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 22-year-old man presents with recurrent episodes of hematuria
occurring within 48 hours of upper respiratory infections. Renal
biopsy demonstrates mesangial deposition of IgA-containing
immune complexes. Which immunologic mechanism is primarily
responsible for this condition?
A. Type I hypersensitivity
B. Type II hypersensitivity
C. Type III hypersensitivity
D. Type IV hypersensitivity
Rationale: IgA nephropathy (Berger disease) results from immune
complex deposition within the mesangium. Immune complex-
mediated injury is classified as a Type III hypersensitivity reaction.
Activation of complement and recruitment of inflammatory cells lead
to glomerular injury and episodic hematuria.
2. A patient with chronic alcohol abuse develops confusion,
ophthalmoplegia, and ataxia. Deficiency of which vitamin is most
likely responsible?
A. Riboflavin
B. Pyridoxine
,C. Folate
D. Thiamine
Rationale: Wernicke encephalopathy is caused by thiamine (vitamin
B1) deficiency. Thiamine is a cofactor for pyruvate dehydrogenase, α-
ketoglutarate dehydrogenase, branched-chain ketoacid
dehydrogenase, and transketolase. Deficiency impairs cerebral energy
metabolism.
3. A mutation causes constitutive activation of adenylate cyclase
within endocrine cells. Which intracellular messenger will be
increased?
A. IP3
B. DAG
C. Calcium
D. cAMP
Rationale: Adenylate cyclase converts ATP into cyclic AMP.
Constitutive activation leads to elevated intracellular cAMP levels and
persistent activation of protein kinase A-mediated signaling
pathways.
4. A patient develops severe hypotension following septic shock.
Which inflammatory mediator is most directly responsible for
widespread vasodilation?
A. Histamine
B. IL-4
C. Nitric oxide
D. Bradykinin
Rationale: Inducible nitric oxide synthase in macrophages produces
large quantities of nitric oxide during sepsis. Excess NO causes
profound vasodilation and contributes significantly to septic shock.
, 5. A researcher blocks mitochondrial cytochrome oxidase activity.
Which component of the electron transport chain is inhibited?
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
Rationale: Cytochrome oxidase corresponds to Complex IV of the
electron transport chain. It transfers electrons to molecular oxygen,
producing water. Inhibition prevents oxidative phosphorylation.
6. A child develops recurrent infections with catalase-positive
organisms. Neutrophil oxidative burst testing is abnormal. Which
disease is most likely?
A. Leukocyte adhesion deficiency
B. Chediak-Higashi syndrome
C. Chronic granulomatous disease
D. Hyper-IgE syndrome
Rationale: Chronic granulomatous disease results from NADPH
oxidase deficiency, causing defective respiratory burst and impaired
killing of catalase-positive organisms.
7. A patient has hyperpigmentation, hypotension, hyponatremia,
and hyperkalemia. Which hormone deficiency explains these
findings?
A. ACTH
B. ADH
C. Cortisol
D. Aldosterone
, Rationale: Primary adrenal insufficiency causes aldosterone
deficiency, leading to sodium loss, potassium retention, volume
depletion, and hypotension.
8. A drug selectively blocks L-type calcium channels in cardiac nodal
tissue. Which effect is expected?
A. Increased AV conduction
B. Increased heart rate
C. Decreased AV nodal conduction
D. Increased contractility
Rationale: Calcium channel blockers such as verapamil decrease
calcium influx in SA and AV nodal tissue, slowing conduction and
reducing heart rate.
9. During fasting, which enzyme becomes most active in adipocytes?
A. Lipoprotein lipase
B. Acetyl-CoA carboxylase
C. Fatty acid synthase
D. Hormone-sensitive lipase
Rationale: Hormone-sensitive lipase is activated by glucagon and
epinephrine, mobilizing stored triglycerides into free fatty acids during
fasting.
10. A patient with nephrotic syndrome develops generalized
edema. Which Starling force alteration is primarily responsible?
A. Increased capillary hydrostatic pressure
B. Increased interstitial oncotic pressure
C. Decreased plasma oncotic pressure
D. Decreased capillary permeability
Foundational Biomedical Sciences Exam
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A 22-year-old man presents with recurrent episodes of hematuria
occurring within 48 hours of upper respiratory infections. Renal
biopsy demonstrates mesangial deposition of IgA-containing
immune complexes. Which immunologic mechanism is primarily
responsible for this condition?
A. Type I hypersensitivity
B. Type II hypersensitivity
C. Type III hypersensitivity
D. Type IV hypersensitivity
Rationale: IgA nephropathy (Berger disease) results from immune
complex deposition within the mesangium. Immune complex-
mediated injury is classified as a Type III hypersensitivity reaction.
Activation of complement and recruitment of inflammatory cells lead
to glomerular injury and episodic hematuria.
2. A patient with chronic alcohol abuse develops confusion,
ophthalmoplegia, and ataxia. Deficiency of which vitamin is most
likely responsible?
A. Riboflavin
B. Pyridoxine
,C. Folate
D. Thiamine
Rationale: Wernicke encephalopathy is caused by thiamine (vitamin
B1) deficiency. Thiamine is a cofactor for pyruvate dehydrogenase, α-
ketoglutarate dehydrogenase, branched-chain ketoacid
dehydrogenase, and transketolase. Deficiency impairs cerebral energy
metabolism.
3. A mutation causes constitutive activation of adenylate cyclase
within endocrine cells. Which intracellular messenger will be
increased?
A. IP3
B. DAG
C. Calcium
D. cAMP
Rationale: Adenylate cyclase converts ATP into cyclic AMP.
Constitutive activation leads to elevated intracellular cAMP levels and
persistent activation of protein kinase A-mediated signaling
pathways.
4. A patient develops severe hypotension following septic shock.
Which inflammatory mediator is most directly responsible for
widespread vasodilation?
A. Histamine
B. IL-4
C. Nitric oxide
D. Bradykinin
Rationale: Inducible nitric oxide synthase in macrophages produces
large quantities of nitric oxide during sepsis. Excess NO causes
profound vasodilation and contributes significantly to septic shock.
, 5. A researcher blocks mitochondrial cytochrome oxidase activity.
Which component of the electron transport chain is inhibited?
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
Rationale: Cytochrome oxidase corresponds to Complex IV of the
electron transport chain. It transfers electrons to molecular oxygen,
producing water. Inhibition prevents oxidative phosphorylation.
6. A child develops recurrent infections with catalase-positive
organisms. Neutrophil oxidative burst testing is abnormal. Which
disease is most likely?
A. Leukocyte adhesion deficiency
B. Chediak-Higashi syndrome
C. Chronic granulomatous disease
D. Hyper-IgE syndrome
Rationale: Chronic granulomatous disease results from NADPH
oxidase deficiency, causing defective respiratory burst and impaired
killing of catalase-positive organisms.
7. A patient has hyperpigmentation, hypotension, hyponatremia,
and hyperkalemia. Which hormone deficiency explains these
findings?
A. ACTH
B. ADH
C. Cortisol
D. Aldosterone
, Rationale: Primary adrenal insufficiency causes aldosterone
deficiency, leading to sodium loss, potassium retention, volume
depletion, and hypotension.
8. A drug selectively blocks L-type calcium channels in cardiac nodal
tissue. Which effect is expected?
A. Increased AV conduction
B. Increased heart rate
C. Decreased AV nodal conduction
D. Increased contractility
Rationale: Calcium channel blockers such as verapamil decrease
calcium influx in SA and AV nodal tissue, slowing conduction and
reducing heart rate.
9. During fasting, which enzyme becomes most active in adipocytes?
A. Lipoprotein lipase
B. Acetyl-CoA carboxylase
C. Fatty acid synthase
D. Hormone-sensitive lipase
Rationale: Hormone-sensitive lipase is activated by glucagon and
epinephrine, mobilizing stored triglycerides into free fatty acids during
fasting.
10. A patient with nephrotic syndrome develops generalized
edema. Which Starling force alteration is primarily responsible?
A. Increased capillary hydrostatic pressure
B. Increased interstitial oncotic pressure
C. Decreased plasma oncotic pressure
D. Decreased capillary permeability
