CN Nutritional Science & Biochemistry 2 — Questions and Answers
Question 1: Which enzyme catalyzes the rate-limiting step of glycolysis?
- Phosphofructokinase-1 (Correct answer)
- Hexokinase
- Pyruvate kinase
- Aldolase
Correct answer: Phosphofructokinase-1
Phosphofructokinase-1 is the committed, rate-limiting enzyme of glycolysis.
Question 2: Which vitamin functions as a coenzyme in the form of FAD?
- Riboflavin (B2) (Correct answer)
- Thiamine (B1)
- Niacin (B3)
- Folate (B9)
Correct answer: Riboflavin (B2)
Riboflavin is the precursor of flavin adenine dinucleotide (FAD).
Question 3: The final electron acceptor in the mitochondrial electron transport chain is:
- Oxygen (Correct answer)
- NAD+
- Cytochrome c
- Coenzyme Q
Correct answer: Oxygen
Molecular oxygen accepts electrons at complex IV to form water.
Question 4: Which amino acid is considered conditionally essential during illness or stress?
- Glutamine (Correct answer)
- Leucine
- Lysine
- Valine
Correct answer: Glutamine
Glutamine becomes essential when metabolic demand exceeds synthesis capacity.
Question 5: Gluconeogenesis primarily occurs in which organ?
- Liver (Correct answer)
- Pancreas
- Skeletal muscle
- Spleen
Correct answer: Liver
The liver is the main site of glucose synthesis from non-carbohydrate precursors.
Question 6: Which lipoprotein is primarily responsible for reverse cholesterol transport?
- HDL (Correct answer)
- LDL
- VLDL
- Chylomicron
Correct answer: HDL
HDL carries cholesterol from peripheral tissues back to the liver.
Question 7: The digestion of dietary protein begins in the stomach with which enzyme?
- Pepsin (Correct answer)
- Trypsin
- Amylase
- Lipase
Correct answer: Pepsin
Pepsin, activated from pepsinogen by acid, initiates protein breakdown.
CN Nutritional Science & Biochemistry 2
Which enzyme catalyzes the rate-limiting step of glycolysis?