, Question 1
A patient with chronic pancreatitis and steatorrhea is at risk for deficiency of
which vitamin due to impaired absorption?
A. Vitamin C
B. Vitamin B12
C. Vitamin D
D. Folate
Correct Answer: C - Vitamin D
RATIONALE
Vitamin D is a fat-soluble vitamin requiring bile salts and pancreatic
lipase for absorption; steatorrhea impairs this process. Vitamin C,
B12, and folate are water-soluble and absorbed via different
mechanisms.
Question 2
Which statement best describes the role of uncoupling protein 1 (UCP1) in
brown adipose tissue?
A. It increases ATP synthesis by enhancing oxidative phosphorylation.
B. It dissipates the proton gradient to generate heat instead of ATP.
C. It facilitates fatty acid oxidation in the mitochondria.
D. It promotes glucose uptake via insulin-independent mechanisms.
Correct Answer: B - It dissipates the proton gradient to generate
heat instead of ATP.
RATIONALE
UCP1 uncouples oxidative phosphorylation by allowing protons to
leak across the inner mitochondrial membrane, producing heat. It does
not increase ATP synthesis, directly oxidize fatty acids, or promote
glucose uptake.
Page 2
, Question 3
A patient on warfarin therapy should maintain consistent intake of which
vitamin to avoid fluctuations in INR?
A. Vitamin E
B. Vitamin K
C. Vitamin A
D. Vitamin D
Correct Answer: B - Vitamin K
RATIONALE
Vitamin K is essential for clotting factor synthesis and interacts with
warfarin, which antagonizes its action. Consistent intake prevents INR
instability. Other vitamins do not directly affect warfarin's
anticoagulant effect.
Question 4
Which of the following best explains why folate supplementation can mask
vitamin B12 deficiency?
A. Folate enhances B12 absorption, delaying depletion.
B. Folate can correct megaloblastic anemia but not neurological damage.
C. Folate competes with B12 for transport proteins.
D. Folate increases B12 excretion, worsening deficiency.
Correct Answer: B - Folate can correct megaloblastic anemia but
not neurological damage.
RATIONALE
Folate can reverse the hematological manifestations of B12 deficiency
but does not prevent or reverse neurological damage, potentially
delaying diagnosis. It does not enhance absorption, compete for
transport, or increase excretion.
Page 3
, Question 5
In the context of protein-energy malnutrition, which biochemical marker is
most sensitive to acute changes in protein status?
A. Albumin
B. Prealbumin
C. Transferrin
D. C-reactive protein
Correct Answer: B - Prealbumin
RATIONALE
Prealbumin (transthyretin) has a short half-life (~2 days) and is more
sensitive to acute protein changes than albumin or transferrin. CRP is
an inflammatory marker, not a direct indicator of protein status.
Question 6
Which of the following is a primary function of vitamin C in collagen
synthesis?
A. It serves as a cofactor for prolyl and lysyl hydroxylases.
B. It provides energy for peptide bond formation.
C. It acts as a structural component of collagen fibers.
D. It regulates gene expression for collagen types.
Correct Answer: A - It serves as a cofactor for prolyl and lysyl
hydroxylases.
RATIONALE
Vitamin C is required as a reducing agent for prolyl and lysyl
hydroxylases, which stabilize collagen triple helices. It does not
provide energy, is not a structural component, and does not directly
regulate gene expression.
Page 4
A patient with chronic pancreatitis and steatorrhea is at risk for deficiency of
which vitamin due to impaired absorption?
A. Vitamin C
B. Vitamin B12
C. Vitamin D
D. Folate
Correct Answer: C - Vitamin D
RATIONALE
Vitamin D is a fat-soluble vitamin requiring bile salts and pancreatic
lipase for absorption; steatorrhea impairs this process. Vitamin C,
B12, and folate are water-soluble and absorbed via different
mechanisms.
Question 2
Which statement best describes the role of uncoupling protein 1 (UCP1) in
brown adipose tissue?
A. It increases ATP synthesis by enhancing oxidative phosphorylation.
B. It dissipates the proton gradient to generate heat instead of ATP.
C. It facilitates fatty acid oxidation in the mitochondria.
D. It promotes glucose uptake via insulin-independent mechanisms.
Correct Answer: B - It dissipates the proton gradient to generate
heat instead of ATP.
RATIONALE
UCP1 uncouples oxidative phosphorylation by allowing protons to
leak across the inner mitochondrial membrane, producing heat. It does
not increase ATP synthesis, directly oxidize fatty acids, or promote
glucose uptake.
Page 2
, Question 3
A patient on warfarin therapy should maintain consistent intake of which
vitamin to avoid fluctuations in INR?
A. Vitamin E
B. Vitamin K
C. Vitamin A
D. Vitamin D
Correct Answer: B - Vitamin K
RATIONALE
Vitamin K is essential for clotting factor synthesis and interacts with
warfarin, which antagonizes its action. Consistent intake prevents INR
instability. Other vitamins do not directly affect warfarin's
anticoagulant effect.
Question 4
Which of the following best explains why folate supplementation can mask
vitamin B12 deficiency?
A. Folate enhances B12 absorption, delaying depletion.
B. Folate can correct megaloblastic anemia but not neurological damage.
C. Folate competes with B12 for transport proteins.
D. Folate increases B12 excretion, worsening deficiency.
Correct Answer: B - Folate can correct megaloblastic anemia but
not neurological damage.
RATIONALE
Folate can reverse the hematological manifestations of B12 deficiency
but does not prevent or reverse neurological damage, potentially
delaying diagnosis. It does not enhance absorption, compete for
transport, or increase excretion.
Page 3
, Question 5
In the context of protein-energy malnutrition, which biochemical marker is
most sensitive to acute changes in protein status?
A. Albumin
B. Prealbumin
C. Transferrin
D. C-reactive protein
Correct Answer: B - Prealbumin
RATIONALE
Prealbumin (transthyretin) has a short half-life (~2 days) and is more
sensitive to acute protein changes than albumin or transferrin. CRP is
an inflammatory marker, not a direct indicator of protein status.
Question 6
Which of the following is a primary function of vitamin C in collagen
synthesis?
A. It serves as a cofactor for prolyl and lysyl hydroxylases.
B. It provides energy for peptide bond formation.
C. It acts as a structural component of collagen fibers.
D. It regulates gene expression for collagen types.
Correct Answer: A - It serves as a cofactor for prolyl and lysyl
hydroxylases.
RATIONALE
Vitamin C is required as a reducing agent for prolyl and lysyl
hydroxylases, which stabilize collagen triple helices. It does not
provide energy, is not a structural component, and does not directly
regulate gene expression.
Page 4
