Fig. 2
From: Long range physical cell-to-cell signalling via mitochondria inside membrane nanotubes: a hypothesis
The two possible physical energy transmission mechanisms in mitochondria: a electrical/electrochemical, and b optical (light). The arrows indicate the possible transmission directions. 1: proton conductance along the mitochondrial membrane. Whereas the existence of mechanism a is experimentally proven, mechanism b is currently only predicted by theory and no experimental investigation into the correctness of the prediction has yet been published