Supercomplexes in ETC
Quite many older studies and teaching materials show complexes I … IV in a consequential way, however latest studies started talking about supercomplexes which don’t necessary include all four complexes (complex V stands out anyway).
This paper about CQ10 has a good illustration, which shows that Complexes I, III and IV form a supercomplex, while Complex II forms another supercomplex without Complex I (they call it respirosomes).
What I also like about this picture is inclusion of a few other proteins that contribute to supply of electrons. E.g. did you know that choline can supply electrons directly to ETC and serve as a fuel (and becomes betaine aldehyde), isn’t that cool?