Figure 4: Schematic representation shows that the synchronized antiphase oscillations of the oscillatory ATP-producing metabolic pathways (glycolysis and mitochondrial respiration) and ATP-consuming pathways (PPRP and nucleotide synthesis) play a key role in generation or maintenance of ATP oscillations during chondrogenesis. White and black boxes represent oscillatory metabolic pathways in phase with ATP and in antiphase with ATP, respectively. Question marks indicate the unknown factors which are involved in ATP oscillations.