Certified Nutrition Specialist Final Exam/ Questions with
Correct Verified Answers – Latest Update 2026.
Question 1: Which hormone primarily stimulates
glycogenolysis in the liver?
A) Insulin
B) Glucagon
C) Cortisol
D) Thyroxine
Answer: B
Rationale: Glucagon binds to hepatic receptors, activating cAMP
and protein kinase A, which phosphorylate glycogen
phosphorylase, leading to glycogen breakdown. This is a
catabolic hormone that raises blood glucose .
Question 2: What is the rate-limiting enzyme of the glycolytic
pathway?
1
,A) Hexokinase
B) Phosphofructokinase-1 (PFK-1)
C) Pyruvate kinase
D) Aldolase
Answer: B
Rationale: Phosphofructokinase-1 (PFK-1) is the rate-limiting
enzyme of glycolysis. It is allosterically regulated by ATP
(inhibitor), AMP (activator), and citrate (inhibitor), controlling the
flow of glucose through glycolysis .
Question 3: Which enzyme catalyzes the conversion of
phosphoenolpyruvate to pyruvate during glycolysis?
A) Hexokinase
B) Phosphofructokinase-1
C) Pyruvate kinase
D) Lactate dehydrogenase
Answer: C
2
,Rationale: Pyruvate kinase transfers a phosphate group from
phosphoenolpyruvate (PEP) to ADP, forming ATP and pyruvate in
the final step of glycolysis. This is an irreversible, highly
regulated step .
Question 4: During the citric acid cycle, which coenzyme
accepts electrons to become NADH?
A) FAD
B) Coenzyme Q10
C) NAD⁺
D) Biotin
Answer: C
Rationale: NAD⁺ is reduced to NADH at three points in the Krebs
cycle (isocitrate dehydrogenase, α-ketoglutarate
dehydrogenase, and malate dehydrogenase), carrying electrons
to the electron transport chain .
3
, Question 5: Which vitamin functions as a cofactor for the
enzyme pyruvate dehydrogenase?
A) Vitamin B1 (thiamine)
B) Vitamin B2 (riboflavin)
C) Vitamin B3 (niacin)
D) Vitamin B5 (pantothenic acid)
Answer: A
Rationale: Thiamine pyrophosphate (TPP) is the active cofactor
for pyruvate dehydrogenase, linking glycolysis to the Krebs
cycle. Thiamine deficiency impairs carbohydrate metabolism .
Question 6: Which macronutrient provides the highest thermic
effect of food (TEF)?
A) Carbohydrate
B) Protein
4
Correct Verified Answers – Latest Update 2026.
Question 1: Which hormone primarily stimulates
glycogenolysis in the liver?
A) Insulin
B) Glucagon
C) Cortisol
D) Thyroxine
Answer: B
Rationale: Glucagon binds to hepatic receptors, activating cAMP
and protein kinase A, which phosphorylate glycogen
phosphorylase, leading to glycogen breakdown. This is a
catabolic hormone that raises blood glucose .
Question 2: What is the rate-limiting enzyme of the glycolytic
pathway?
1
,A) Hexokinase
B) Phosphofructokinase-1 (PFK-1)
C) Pyruvate kinase
D) Aldolase
Answer: B
Rationale: Phosphofructokinase-1 (PFK-1) is the rate-limiting
enzyme of glycolysis. It is allosterically regulated by ATP
(inhibitor), AMP (activator), and citrate (inhibitor), controlling the
flow of glucose through glycolysis .
Question 3: Which enzyme catalyzes the conversion of
phosphoenolpyruvate to pyruvate during glycolysis?
A) Hexokinase
B) Phosphofructokinase-1
C) Pyruvate kinase
D) Lactate dehydrogenase
Answer: C
2
,Rationale: Pyruvate kinase transfers a phosphate group from
phosphoenolpyruvate (PEP) to ADP, forming ATP and pyruvate in
the final step of glycolysis. This is an irreversible, highly
regulated step .
Question 4: During the citric acid cycle, which coenzyme
accepts electrons to become NADH?
A) FAD
B) Coenzyme Q10
C) NAD⁺
D) Biotin
Answer: C
Rationale: NAD⁺ is reduced to NADH at three points in the Krebs
cycle (isocitrate dehydrogenase, α-ketoglutarate
dehydrogenase, and malate dehydrogenase), carrying electrons
to the electron transport chain .
3
, Question 5: Which vitamin functions as a cofactor for the
enzyme pyruvate dehydrogenase?
A) Vitamin B1 (thiamine)
B) Vitamin B2 (riboflavin)
C) Vitamin B3 (niacin)
D) Vitamin B5 (pantothenic acid)
Answer: A
Rationale: Thiamine pyrophosphate (TPP) is the active cofactor
for pyruvate dehydrogenase, linking glycolysis to the Krebs
cycle. Thiamine deficiency impairs carbohydrate metabolism .
Question 6: Which macronutrient provides the highest thermic
effect of food (TEF)?
A) Carbohydrate
B) Protein
4
