Many of the redox centers that comprise the electron transport system (ETS) are integral components of larger protein complexes, whereas others, such as , freely diffuse within the membrane as they ferry electrons between other ETS components.

Electron Transport Chain

Explanation:

Quinones is right answerThe Quinones are network site,that the lipid -soluble carriers that adjusted electron and proton between The macromolecular complex which is embedded in the membrane layer and largeThe Bacteria used related quinones and ubiquinone such as menaquinone(Vitamin K2)The protons are act as pumped from the oxygen decreases to form water and the mitochondrial matrix to the middle membrane space

Just dont put scarce