. "A part of the respiratory chain located in the plasma membrane, containing the 13 polypeptide subunits of cytochrome c oxidase, including cytochrome a and cytochrome a3. Catalyzes the oxidation of reduced cytochrome c by dioxygen (O2). Examples of this component are found in Bacterial species." . . . . "respiratory chain complex IV" . "cytochrome c oxidase complex" . "plasma membrane respiratory chain complex IV" . . . .