COMSAE Phase 1 Form 114 Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. Which artery is the primary blood supply to the lateral aspect of the
cerebral hemisphere (including the primary motor cortex for the face
and upper limb)?
A. Anterior cerebral artery
B. Posterior cerebral artery
C. Middle cerebral artery
D. Basilar artery
Rationale: The middle cerebral artery supplies the lateral convexity
of the cerebral hemisphere including motor and sensory cortices for
face and upper limb.
2. A patient has a deficiency of pyruvate dehydrogenase. Which
metabolic consequence is most likely?
A. Increased conversion of pyruvate to acetyl-CoA
B. Accumulation of lactate (lactic acidosis)
C. Increased gluconeogenesis from acetyl-CoA
D. Increased activity of Krebs cycle
Rationale: Pyruvate dehydrogenase deficiency prevents pyruvate
, entering the TCA cycle as acetyl-CoA, so pyruvate is shunted to
lactate causing lactic acidosis.
3. Which cranial nerve mediates the afferent limb of the corneal blink
reflex?
A. Facial nerve (VII)
B. Glossopharyngeal nerve (IX)
C. Trigeminal nerve (V — ophthalmic branch V1)
D. Oculomotor nerve (III)
Rationale: The ophthalmic division (V1) of trigeminal nerve senses
corneal stimulation (afferent); facial nerve (VII) causes the efferent
blink.
4. Which immunoglobulin is the first to be produced in a primary
immune response?
A. IgA
B. IgE
C. IgM
D. IgG
Rationale: IgM is the first antibody isotype produced in a primary
humoral immune response before class switching to IgG, IgA, or IgE.
5. A 60-year-old smoker presents with squamous cell carcinoma of the
lung. Which paraneoplastic syndrome is most commonly associated
with squamous cell carcinoma?
A. Lambert–Eaton myasthenic syndrome
B. Hypercalcemia (via PTHrP production)
C. SIADH (syndrome of inappropriate ADH)
D. Cushing’s syndrome (ACTH production)
Rationale: Squamous cell carcinoma of the lung commonly secretes
parathyroid hormone–related peptide (PTHrP), causing
hypercalcemia.
, 6. During muscle contraction, which ion is directly responsible for
binding to troponin and initiating cross-bridge cycling?
A. Sodium (Na+)
B. Calcium (Ca2+)
C. Potassium (K+)
D. Magnesium (Mg2+)
Rationale: Calcium binds troponin C, causing conformational change
that moves tropomyosin and allows actin–myosin cross-bridge
formation.
7. Which vitamin deficiency causes pernicious anemia due to impaired
DNA synthesis and megaloblastic changes?
A. Vitamin C
B. Vitamin D
C. Vitamin B12 (cobalamin)
D. Vitamin K
Rationale: Vitamin B12 deficiency leads to impaired DNA synthesis in
rapidly dividing cells causing megaloblastic anemia; pernicious
anemia is due to intrinsic factor deficiency.
8. Which bacteria is the most common cause of community-acquired
pneumonia in adults?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Mycoplasma pneumoniae
D. Legionella pneumophila
Rationale: Streptococcus pneumoniae is the most common cause of
community-acquired pneumonia overall, especially typical lobar
pneumonia in adults.
9. Which cell type is primarily involved in acute inflammation and is the
main phagocyte in the first 24–48 hours?
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. Which artery is the primary blood supply to the lateral aspect of the
cerebral hemisphere (including the primary motor cortex for the face
and upper limb)?
A. Anterior cerebral artery
B. Posterior cerebral artery
C. Middle cerebral artery
D. Basilar artery
Rationale: The middle cerebral artery supplies the lateral convexity
of the cerebral hemisphere including motor and sensory cortices for
face and upper limb.
2. A patient has a deficiency of pyruvate dehydrogenase. Which
metabolic consequence is most likely?
A. Increased conversion of pyruvate to acetyl-CoA
B. Accumulation of lactate (lactic acidosis)
C. Increased gluconeogenesis from acetyl-CoA
D. Increased activity of Krebs cycle
Rationale: Pyruvate dehydrogenase deficiency prevents pyruvate
, entering the TCA cycle as acetyl-CoA, so pyruvate is shunted to
lactate causing lactic acidosis.
3. Which cranial nerve mediates the afferent limb of the corneal blink
reflex?
A. Facial nerve (VII)
B. Glossopharyngeal nerve (IX)
C. Trigeminal nerve (V — ophthalmic branch V1)
D. Oculomotor nerve (III)
Rationale: The ophthalmic division (V1) of trigeminal nerve senses
corneal stimulation (afferent); facial nerve (VII) causes the efferent
blink.
4. Which immunoglobulin is the first to be produced in a primary
immune response?
A. IgA
B. IgE
C. IgM
D. IgG
Rationale: IgM is the first antibody isotype produced in a primary
humoral immune response before class switching to IgG, IgA, or IgE.
5. A 60-year-old smoker presents with squamous cell carcinoma of the
lung. Which paraneoplastic syndrome is most commonly associated
with squamous cell carcinoma?
A. Lambert–Eaton myasthenic syndrome
B. Hypercalcemia (via PTHrP production)
C. SIADH (syndrome of inappropriate ADH)
D. Cushing’s syndrome (ACTH production)
Rationale: Squamous cell carcinoma of the lung commonly secretes
parathyroid hormone–related peptide (PTHrP), causing
hypercalcemia.
, 6. During muscle contraction, which ion is directly responsible for
binding to troponin and initiating cross-bridge cycling?
A. Sodium (Na+)
B. Calcium (Ca2+)
C. Potassium (K+)
D. Magnesium (Mg2+)
Rationale: Calcium binds troponin C, causing conformational change
that moves tropomyosin and allows actin–myosin cross-bridge
formation.
7. Which vitamin deficiency causes pernicious anemia due to impaired
DNA synthesis and megaloblastic changes?
A. Vitamin C
B. Vitamin D
C. Vitamin B12 (cobalamin)
D. Vitamin K
Rationale: Vitamin B12 deficiency leads to impaired DNA synthesis in
rapidly dividing cells causing megaloblastic anemia; pernicious
anemia is due to intrinsic factor deficiency.
8. Which bacteria is the most common cause of community-acquired
pneumonia in adults?
A. Haemophilus influenzae
B. Streptococcus pneumoniae
C. Mycoplasma pneumoniae
D. Legionella pneumophila
Rationale: Streptococcus pneumoniae is the most common cause of
community-acquired pneumonia overall, especially typical lobar
pneumonia in adults.
9. Which cell type is primarily involved in acute inflammation and is the
main phagocyte in the first 24–48 hours?
