Which electron carrier is primarily involved in the redox reactions of cellular respiration?

• A. NAD\(^+\) (Nicotinamide adenine dinucleotide)
• B. ATP (Adenosine triphosphate)
• C. cAMP (Cyclic adenosine monophosphate)
• D. FADH\(_2\) (Flavin adenine dinucleotide)

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the context of the problem. Cellular respiration is a metabolic process where cells convert biochemical energy from nutrients into ATP, and it involves redox reactions (oxidation-reduction reactions). These reactions require electron carriers to transfer electrons.
2. Step 2: Review the role of NAD\(^+\) (Nicotinamide adenine dinucleotide). NAD\(^+\) is a key electron carrier in cellular respiration. It accepts electrons during glycolysis and the citric acid cycle, becoming NADH, which then donates electrons to the electron transport chain.
3. Step 3: Examine the role of FADH\(_2\) (Flavin adenine dinucleotide). FADH\(_2\) is another electron carrier involved in cellular respiration, specifically in the citric acid cycle. It donates electrons to the electron transport chain but is less prominent compared to NAD\(^+\).
4. Step 4: Clarify the roles of ATP and cAMP. ATP is the primary energy currency of the cell, not an electron carrier. cAMP is a signaling molecule involved in various cellular processes, not directly involved in redox reactions of cellular respiration.
5. Step 5: Conclude that NAD\(^+\) is the primary electron carrier involved in the redox reactions of cellular respiration, as it plays a central role in transferring electrons during glycolysis, the citric acid cycle, and the electron transport chain.