Final answer:
The citric acid cycle produces NADH and FADH₂, which transfer high-energy electrons to the electron transport chain, ultimately contributing to ATP synthesis.
Step-by-step explanation:
The citric acid cycle, also known as the Krebs cycle or the tricarboxylic acid (TCA) cycle, occurs in the mitochondrial matrix and is crucial for cellular respiration. This cycle involves the transformation of pyruvate, derived from glycolysis, into acetyl CoA and then into CO₂ and high-energy electrons. These high-energy electrons are captured by the coenzymes NAD+ and FAD, converting them into the electron carriers NADH and FADH₂ respectively.
The activated carriers, NADH and FADH₂ then transfer these high-energy electrons to the electron transport chain, which uses the energy released during electron transport to pump protons across the membrane, creating a gradient used for ATP synthesis. Additionally, each cycle results in the production of ATP or GTP through substrate-level phosphorylation. The end products of the electron transport chain are water and additional molecules of ATP, the energy currency of the cell.