NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
1
Exam Section 1: Item 1 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
1. A 40-year-old woman at 5 months' gestation comes to
the physician for amniocentesis. Results show a normal
46,XY karyotype of the fetus. Four months later, the
newborn is delivered and
examination shows a female phenotype with mild clitoral
enlargement. Ultrasonography shows the presence of
male but not female genital ducts. This newborn most
likely has a mutation of
the gene of which of the following factors?
A) Anti-paramesonephric (müllerian) hormone
B) 5a-Reductase
C) SRY protein
D) Steroid sulfatase
E) Zinc finger transcription factor Wilms tumor 1
Correct Answer: B.
5a-Reductase is an enzyme that catalyzes the
metabolism of testosterone to dihydrotestosterone (DHT).
Testosterone promotes the development of the
mesonephric (wolffian) duct that develops
,NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
into the seminal vesicles, epididymis, vas defe -
CORRECT ANSWERS ✔✔Objective: 5a-Reductase
catalyzes the metabolism of testosterone to DHT.
Individuals with 5a-reductase deficiency exhibit
decreased concentrations of DHT and impaired virilization
of the male urogenital tract. Individuals with 5a-reductase
deficiency appear phenotypically female externally or
may have ambiguous external genitalia, with normal
male internal genitalia.
II
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2
Exam Section 1: Item 2 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
2. A 16-year-old girl with cystic fibrosis is brought to the
physician because of a 3-week history of generalized
,NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
weakness, numbness and tingling of her arms and legs,
and difficulty walking. She
has not adhered to her medication regimen during the
past 6 months. She appears alert and oriented. Her vital
signs are within normal limits. Physical examination
shows bilateral weakness
and decreased deep tendon reflexes in the upper and
lower extremities. She walks with an ataxic gait. The most
likely cause of these findings is a deficiency of which of
the following?
A) Folic acid
B) Vitamin A
C) Vitamin B, (pyridoxine)
D) Vitamin D
E) Vitamin E
Correct Answer: E.
Vitamin E is an antioxidant that protects erythrocytes and
cells from free radical damage. Deficiency may present
with hemolytic anemia and generalize - CORRECT
ANSWERS ✔✔Objective: Vitamin E is an antioxidant
that protects cells from free radical damage. Deficiency
may present with hemolytic anemia and generalized
muscle weakness. It can have a
similar presentation to vitamin B12 deficiency with
posterior column and spinocerebellar tract demyelination.
, NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
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3
Exam Section 1: Item 3 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
3. A 55-year-old woman comes to the physician because
of a 6-month history of progressive shortness of breath
while climbing stairs and constant fatigue. She is 163 cm
(5 ft 4 in) tall and
weighs 107 kg (235 lb); BMI is 40 kg/m2. Her blood
pressure is 170/110 mm Hg on three separate readings.
Physical examination shows no other abnormalities.
Echocardiography shows an
ejection fraction of 45%. There are no regional wall
motion or valvular abnormalities. An ECG shows that the
Answers ( Latest 2025 )
1
Exam Section 1: Item 1 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
1. A 40-year-old woman at 5 months' gestation comes to
the physician for amniocentesis. Results show a normal
46,XY karyotype of the fetus. Four months later, the
newborn is delivered and
examination shows a female phenotype with mild clitoral
enlargement. Ultrasonography shows the presence of
male but not female genital ducts. This newborn most
likely has a mutation of
the gene of which of the following factors?
A) Anti-paramesonephric (müllerian) hormone
B) 5a-Reductase
C) SRY protein
D) Steroid sulfatase
E) Zinc finger transcription factor Wilms tumor 1
Correct Answer: B.
5a-Reductase is an enzyme that catalyzes the
metabolism of testosterone to dihydrotestosterone (DHT).
Testosterone promotes the development of the
mesonephric (wolffian) duct that develops
,NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
into the seminal vesicles, epididymis, vas defe -
CORRECT ANSWERS ✔✔Objective: 5a-Reductase
catalyzes the metabolism of testosterone to DHT.
Individuals with 5a-reductase deficiency exhibit
decreased concentrations of DHT and impaired virilization
of the male urogenital tract. Individuals with 5a-reductase
deficiency appear phenotypically female externally or
may have ambiguous external genitalia, with normal
male internal genitalia.
II
Next
Score Report
Lab Values
Calculator
Help
Pause
2
Exam Section 1: Item 2 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
2. A 16-year-old girl with cystic fibrosis is brought to the
physician because of a 3-week history of generalized
,NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
weakness, numbness and tingling of her arms and legs,
and difficulty walking. She
has not adhered to her medication regimen during the
past 6 months. She appears alert and oriented. Her vital
signs are within normal limits. Physical examination
shows bilateral weakness
and decreased deep tendon reflexes in the upper and
lower extremities. She walks with an ataxic gait. The most
likely cause of these findings is a deficiency of which of
the following?
A) Folic acid
B) Vitamin A
C) Vitamin B, (pyridoxine)
D) Vitamin D
E) Vitamin E
Correct Answer: E.
Vitamin E is an antioxidant that protects erythrocytes and
cells from free radical damage. Deficiency may present
with hemolytic anemia and generalize - CORRECT
ANSWERS ✔✔Objective: Vitamin E is an antioxidant
that protects cells from free radical damage. Deficiency
may present with hemolytic anemia and generalized
muscle weakness. It can have a
similar presentation to vitamin B12 deficiency with
posterior column and spinocerebellar tract demyelination.
, NBME 27 EDU OBJ Exam Question &
Answers ( Latest 2025 )
Previous
Next
Score Report
Lab Values
Calculator
Help
Pause
3
Exam Section 1: Item 3 of 50
National Board of Medical Examiners'
Comprehensive Basic Science Self-Assessment
3. A 55-year-old woman comes to the physician because
of a 6-month history of progressive shortness of breath
while climbing stairs and constant fatigue. She is 163 cm
(5 ft 4 in) tall and
weighs 107 kg (235 lb); BMI is 40 kg/m2. Her blood
pressure is 170/110 mm Hg on three separate readings.
Physical examination shows no other abnormalities.
Echocardiography shows an
ejection fraction of 45%. There are no regional wall
motion or valvular abnormalities. An ECG shows that the
