Plastoquinone- Found in plants. Type of quinone, a molecular compound made of aromatics. I forget the specifics of its function or pathway, but is involved in the ETC of light dependent rxns
Ubiquinone- as said above, co-enzyme involved in aerobic respiration, specifically the ETC. Generates energy in the form of ATP.
Cytochrome- proteins with heme groups (hemoproteins) Essential for performing redox reactions (oxidation and reduction) during the ETC