Question

which vitamins serve as co - enzymes for energy metabolism?
multiple choice
vitamin a and e
vitamin d and calcium
b - complex vitamins
vitamin a and k

Explanation:

B - complex vitamins (such as thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12)) play crucial roles as co - enzymes in energy metabolism. They are involved in processes like the breakdown of carbohydrates, fats, and proteins to release energy. For example, thiamin is a co - enzyme in the conversion of pyruvate (from carbohydrate breakdown) to acetyl - CoA which enters the citric acid cycle (a key energy - producing pathway). Riboflavin is part of co - enzymes like FAD (flavin adenine dinucleotide) which is involved in electron transport chain reactions related to energy production. Niacin is part of co - enzymes like NAD+ (nicotinamide adenine dinucleotide) which is also essential for redox reactions in energy metabolism.
Vitamin A is mainly related to vision, immune function, and cell growth. Vitamin E is an antioxidant. Vitamin D is related to calcium absorption and bone health (and calcium is a mineral, not a vitamin). Vitamin K is involved in blood clotting.

Answer:

B - complex vitamins