Fig. 1

Mitochondria act as a powerhouse of the cell (a). Metabolic pathways within mitochondria contribute to molecular biosynthesis and the production of ATP. Inside mitochondrial, pyruvate, fatty acids, and amino acids were oxidized and electrons enter to electron transport chain. The production of ATP is facilitated by an electrochemical gradient through oxidative phosphorylation. The role of mitochondria during differentiation (b).The size and number of mitochondria are increased in stem cells along with maturation to the mature cell types. In the progress of differentiation, mitochondria are elongated and the length of crista increase because of active oxidative phosphorylation. It seems that reactive oxygen species and oxygen radicals increase by activation of mitochondrial function. Carnitine palmitoyltransferase I, II: CPT I and II; Cytochrome c: CytC; Flavin adenine dinucleotide: FADH; Nicotinamide adenine dinucleotide: NADH; Reactive oxygen species: ROS; Tricarboxylic acid: TCA; Uncoupling proteins: UCPs