Final answer:
The most common coenzyme involved in energy metabolism is NAD+ (option C). It plays a pivotal role in oxidation-reduction reactions central to the metabolic processes, including glycolysis, the Krebs cycle, and oxidative phosphorylation. NADH, the reduced form of NAD+, is crucial for ATP creation.
Step-by-step explanation:
The correct answer to the question is NAD+ (Nicotinamide Adenine Dinucleotide), which is the most common coenzyme involved in energy metabolism. This means the answer to the question is C) NAD+. NAD+ is essential for many oxidation-reduction reactions, where it acts as a hydride acceptor and is converted into its reduced form, NADH. NADH then carries electrons to the electron transport chain, where it is used in the creation of ATP.
Other coenzymes involved in metabolic processes include FAD (Flavin Adenine Dinucleotide) and NADP+ (Nicotinamide Adenine Dinucleotide Phosphate). FAD is derived from vitamin B2, also known as riboflavin, and its reduced form is FADH2, which also transfers energy during the creation of ATP. NADP+ has an additional phosphate group and is particularly important in photosynthesis and anabolic reactions.
It is important to note that NADP+ and FAD are also integral coenzymes in energy metabolism but NAD+ is the most widely recognized and commonly involved in basic energy extraction processes, particularly in the metabolism of glucose through glycolysis, the Krebs cycle, and oxidative phosphorylation.