Final Answer:
NADH (Nicotinamide Adenine Dinucleotide) is derived from niacin (vitamin B3), and FADH₂ (Flavin Adenine Dinucleotide) is derived from riboflavin (vitamin B2).
Step-by-step explanation:
NADH (Nicotinamide Adenine Dinucleotide):
NADH is generated from niacin, which is a water-soluble B-vitamin. In cellular respiration, during glycolysis and the citric acid cycle, NAD⁺ accepts electrons and a proton to become NADH. This conversion is essential for the transfer of high-energy electrons to the electron transport chain, where they contribute to the production of ATP.
FADH₂ (Flavin Adenine Dinucleotide):
FADH₂ is derived from riboflavin, a B-vitamin that is soluble in water. In the citric acid cycle, during the oxidation of succinate, FAD accepts electrons and protons, forming FADH₂. FADH₂ subsequently delivers these electrons to the electron transport chain, participating in the generation of ATP.
Understanding the origins of NADH and FADH₂ highlights the interconnection between cellular respiration and the essential role of B-vitamins in energy metabolism.
Option A is the answer.