Fig. 1.

Mitochondrial structure and functions during male germ cell development. The mitochondrial lumen is named matrix, where Krebs cycle, mitochondrial DNA replication and proteins biosynthesis occur. The matrix is encompassed by the inner mitochondrial membrane (IMM) and outer mitochondrial membrane (OMM). The IMM can be divided into three parts: inner boundary membrane (IBM) (the part of the IMM running parallel to the OMM), cristae membranes (CMs), which are deep and pleomorphic invaginations occupying the surface area and houses mitochondrial respiration machinery, and cristae junctions (CJs), which are pore- or slit-like membrane structures connecting IBM and CM. Mitochondrial porins, or voltage-dependent anion-selective channels (VDACs) are major metabolite channels in the outer membrane connecting the transport of molecules and mitochondrial metabolism