Why are NADH and FADH2 important in the Citric Acid Cycle?

NADH and FADH2 play a crucial role in cellular respiration, specifically in the process of oxidative phosphorylation. After being generated during the Citric Acid Cycle (also known as the Krebs cycle), they serve as important electron carriers. The primary function of NADH and FADH2 is to transfer high-energy electrons to the electron transport chain located in the inner mitochondrial membrane.

When NADH and FADH2 donate electrons to the electron transport chain, it facilitates a series of redox reactions that ultimately lead to the establishment of a proton gradient across the mitochondrial membrane. This gradient is essential for ATP production, as it drives the activity of ATP synthase, which synthesizes ATP from ADP and inorganic phosphate. Thus, the role of NADH and FADH2 in transferring electrons to the electron transport chain is fundamental for energy production in aerobic organisms.

The other choices do not accurately describe their primary function. While NADH and FADH2 are indeed involved in energy production indirectly through ATP synthesis, they do not produce ATP directly nor do they facilitate gluconeogenesis. Furthermore, they do not inhibit the cycle's operation; rather, they are products of the cycle that indicate the cycle is functioning efficiently.