What does NADH and FADH2 mean exactly and how do they help in respiration ?
NADH is produced during glycolysis, which is the first part of cellular respiration. NADH and FADH2 are both produced during the Krebs Cycle, which is the second part of cellular respiration. The electrons from these molecules are then used in the electron chain during oxidative phosphorylation (the third part of cellular respiration). The electrons are moved along the electron transport chain and then eventually used in ATP production. In short, these molecules are produced during the first two phases of cellular respiration and then used to make ATP in the last phase of cellular respiration.