Summarize what happens during respiration.
In summary, a number of redox reactions in glycolysis or alternate pathways and in the Krebs cycle strip electrons (which carry energy) from glucose molecules and transfer them to molecules of NADH and FADH2. In turn, NADH and FADH2 pass electrons to an electron transport chain. As the electrons move down the electron transport chain, proton pumps use the electrons' energy to actively transport protons (H+) across the membrane, creating a proton concentration gradient. This gradient is then used to create ATP.