(A) “Classical” schematic representation of the mitochondrial oxidative phosphorylation (OXPHOS) system showing its individual components separated from each other, (M) matrix, (IMS) intermembrane space, (IM) inner membrane. (B) Schematic model of the organization of individual components of the respiratory chain (complexes I, III and IV) into a respiratory string. Both figure panels were created based on corresponding figures in [55].