Medical School In-Training Exam (ITE)
Preclinical Questions With Correct Answers
(Verified Answers) Plus Rationales 2026 Q&A |
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Question 1
A 23-year-old man experiences severe pain after a tibial fracture. Which
receptor type primarily mediates fast pain transmission?
A. C fibers
B. A-delta fibers
C. A-beta fibers
D. Gamma motor neurons
Correct answer: B
Rationale: A-delta fibers are myelinated and transmit fast, sharp, well-
localized pain. C fibers transmit slow, dull pain, while A-beta fibers
carry touch/pressure signals.
Question 2
,Which enzyme is deficient in classic phenylketonuria (PKU)?
A. Tyrosinase
B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Dopamine beta-hydroxylase
Correct answer: B
Rationale: PKU is caused by deficiency of phenylalanine hydroxylase,
leading to accumulation of phenylalanine and neurological damage if
untreated.
Question 3
Which part of the nephron is primarily responsible for glucose
reabsorption?
A. Distal convoluted tubule
B. Collecting duct
C. Proximal convoluted tubule
D. Loop of Henle
Correct answer: C
,Rationale: The proximal convoluted tubule reabsorbs nearly all filtered
glucose via SGLT transporters.
Question 4
Which structure is most directly responsible for production of
cerebrospinal fluid (CSF)?
A. Arachnoid granulations
B. Choroid plexus
C. Dura mater
D. Pia mater
Correct answer: B
Rationale: The choroid plexus in the ventricles produces CSF by
filtering plasma and secreting it into ventricular spaces.
Question 5
Which vitamin deficiency leads to Wernicke encephalopathy?
A. Vitamin B1 (thiamine)
B. Vitamin B6 (pyridoxine)
, C. Vitamin B12 (cobalamin)
D. Vitamin C (ascorbic acid)
Correct answer: A
Rationale: Thiamine deficiency causes Wernicke encephalopathy,
characterized by confusion, ataxia, and ophthalmoplegia.
Question 6
Which immunoglobulin is most abundant in serum?
A. IgA
B. IgD
C. IgG
D. IgM
Correct answer: C
Rationale: IgG is the most abundant immunoglobulin in serum and
provides long-term immunity.
Question 7
Which type of hypersensitivity is mediated by IgE?
Preclinical Questions With Correct Answers
(Verified Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
Question 1
A 23-year-old man experiences severe pain after a tibial fracture. Which
receptor type primarily mediates fast pain transmission?
A. C fibers
B. A-delta fibers
C. A-beta fibers
D. Gamma motor neurons
Correct answer: B
Rationale: A-delta fibers are myelinated and transmit fast, sharp, well-
localized pain. C fibers transmit slow, dull pain, while A-beta fibers
carry touch/pressure signals.
Question 2
,Which enzyme is deficient in classic phenylketonuria (PKU)?
A. Tyrosinase
B. Phenylalanine hydroxylase
C. Homogentisate oxidase
D. Dopamine beta-hydroxylase
Correct answer: B
Rationale: PKU is caused by deficiency of phenylalanine hydroxylase,
leading to accumulation of phenylalanine and neurological damage if
untreated.
Question 3
Which part of the nephron is primarily responsible for glucose
reabsorption?
A. Distal convoluted tubule
B. Collecting duct
C. Proximal convoluted tubule
D. Loop of Henle
Correct answer: C
,Rationale: The proximal convoluted tubule reabsorbs nearly all filtered
glucose via SGLT transporters.
Question 4
Which structure is most directly responsible for production of
cerebrospinal fluid (CSF)?
A. Arachnoid granulations
B. Choroid plexus
C. Dura mater
D. Pia mater
Correct answer: B
Rationale: The choroid plexus in the ventricles produces CSF by
filtering plasma and secreting it into ventricular spaces.
Question 5
Which vitamin deficiency leads to Wernicke encephalopathy?
A. Vitamin B1 (thiamine)
B. Vitamin B6 (pyridoxine)
, C. Vitamin B12 (cobalamin)
D. Vitamin C (ascorbic acid)
Correct answer: A
Rationale: Thiamine deficiency causes Wernicke encephalopathy,
characterized by confusion, ataxia, and ophthalmoplegia.
Question 6
Which immunoglobulin is most abundant in serum?
A. IgA
B. IgD
C. IgG
D. IgM
Correct answer: C
Rationale: IgG is the most abundant immunoglobulin in serum and
provides long-term immunity.
Question 7
Which type of hypersensitivity is mediated by IgE?
