Operational definition

Residual mechanism class.

Energy-conserving processes in which a chemical reaction other than a conventional respiratory or photosynthetic electron-transport chain is directly coupled to ion translocation or ion-gradient use.

Examples include:

This category should be used only when the specific mechanism is also recorded; it must not become a miscellaneous substitute for incomplete identification. Proton- and sodium-motive forces support ATP synthesis and other work, while bifurcation, confurcation, and reverse electron transport couple favorable and unfavorable redox reactions in distinct ways. (PubMed Central (PMC))