(Phys.org)—Piece by piece, the circuit diagram for electron transport in the mitochondria has come closer to completion. Each new structure obtained for any of the five respiratory complexes further constrains the assembled puzzle. Eventually, big blocks are arranged into their final placements. The exact composition of the biggest block, the so-called megacomplex, has long eluded researchers. Now, after imaging 140 individual subunits down to 3.9 anstrom resolution, the Full Monty is has been laid bare. Researchers describe in Cell exactly how the human respiratory megacomplex is put together and appears to function.