Phase 5: Spread of disease between humans is occurring in more than one country of one WHO region. Phase 6: Community-level outbreaks are in at least one additional country in a different WHO region from phase 5. A global pandemic is under way.
Figure %: The Electron Transport Chain. The events of the electron transport chain involve NADH and FADH, which act as electron transporters as they flow through the inner membrane space. In complex I, electrons are passed from NADH to the electron transport chain, where they flow through the remaining complexes. NADH is oxidized to NAD in this process.
Oxygen. In the electron transport chain, oxidative phosphorylation occurs over a series of steps in the intermembrane space of the mitochondrion. As the NAD and FAD molecules give up the hydrogen atoms, the hydrogen atoms get split into electrons and protons. Flow of electrons through electron carriers from a higher energy level to lower energy level produces energy, some of which is used to drive the protons out of the matrix into the intermembrane space.