COMSAE Phase 1 Form 114 Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1.
A 45-year-old man presents with fatigue, pallor, and glossitis.
Laboratory tests show macrocytic anemia and hypersegmented
neutrophils. Which of the following is the most likely cause?
A. Iron deficiency
B. Vitamin B12 deficiency
C. Folate deficiency
D. Lead poisoning
Answer: B
Vitamin B12 deficiency leads to megaloblastic anemia characterized
by macrocytosis and hypersegmented neutrophils. It is often
associated with neurologic symptoms due to methylmalonic acid
accumulation, which distinguishes it from folate deficiency.
,2.
Which enzyme is deficient in classic phenylketonuria (PKU)?
A. Tyrosinase
B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Galactose-1-phosphate uridyltransferase
Answer: B
PKU is caused by a deficiency of phenylalanine hydroxylase, leading to
accumulation of phenylalanine and decreased tyrosine production,
which can result in intellectual disability if untreated.
3.
A patient presents with wheezing, hypotension, and urticaria after a
bee sting. Which immunoglobulin mediates this reaction?
A. IgA
B. IgE
C. IgG
D. IgM
Answer: B
,Type I hypersensitivity reactions are mediated by IgE bound to mast
cells, leading to degranulation and release of histamine, causing
anaphylaxis.
4.
Which structure is primarily responsible for urine concentration in the
kidney?
A. Proximal convoluted tubule
B. Loop of Henle
C. Distal convoluted tubule
D. Collecting duct only
Answer: B
The loop of Henle creates the medullary concentration gradient via
the countercurrent multiplier system, essential for urine concentration.
5.
A 60-year-old man with chronic smoking history has hemoptysis and a
central lung mass. Which cancer is most likely?
, A. Adenocarcinoma
B. Small cell carcinoma
C. Squamous cell carcinoma
D. Carcinoid tumor
Answer: C
Squamous cell carcinoma is strongly associated with smoking and
commonly presents as a central lung mass with possible hemoptysis
and paraneoplastic hypercalcemia.
6.
Which vitamin deficiency causes night blindness?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
Answer: A
Vitamin A is required for rhodopsin formation in rod cells; deficiency
leads to impaired dark adaptation and night blindness.
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1.
A 45-year-old man presents with fatigue, pallor, and glossitis.
Laboratory tests show macrocytic anemia and hypersegmented
neutrophils. Which of the following is the most likely cause?
A. Iron deficiency
B. Vitamin B12 deficiency
C. Folate deficiency
D. Lead poisoning
Answer: B
Vitamin B12 deficiency leads to megaloblastic anemia characterized
by macrocytosis and hypersegmented neutrophils. It is often
associated with neurologic symptoms due to methylmalonic acid
accumulation, which distinguishes it from folate deficiency.
,2.
Which enzyme is deficient in classic phenylketonuria (PKU)?
A. Tyrosinase
B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Galactose-1-phosphate uridyltransferase
Answer: B
PKU is caused by a deficiency of phenylalanine hydroxylase, leading to
accumulation of phenylalanine and decreased tyrosine production,
which can result in intellectual disability if untreated.
3.
A patient presents with wheezing, hypotension, and urticaria after a
bee sting. Which immunoglobulin mediates this reaction?
A. IgA
B. IgE
C. IgG
D. IgM
Answer: B
,Type I hypersensitivity reactions are mediated by IgE bound to mast
cells, leading to degranulation and release of histamine, causing
anaphylaxis.
4.
Which structure is primarily responsible for urine concentration in the
kidney?
A. Proximal convoluted tubule
B. Loop of Henle
C. Distal convoluted tubule
D. Collecting duct only
Answer: B
The loop of Henle creates the medullary concentration gradient via
the countercurrent multiplier system, essential for urine concentration.
5.
A 60-year-old man with chronic smoking history has hemoptysis and a
central lung mass. Which cancer is most likely?
, A. Adenocarcinoma
B. Small cell carcinoma
C. Squamous cell carcinoma
D. Carcinoid tumor
Answer: C
Squamous cell carcinoma is strongly associated with smoking and
commonly presents as a central lung mass with possible hemoptysis
and paraneoplastic hypercalcemia.
6.
Which vitamin deficiency causes night blindness?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
Answer: A
Vitamin A is required for rhodopsin formation in rod cells; deficiency
leads to impaired dark adaptation and night blindness.
