This a model from the article: Mitochondrial energetic metabolism: a simplified model of TCA cycle with ATP production. Nazaret C, Heiske M, Thurley K, Mazat JP J. Theor. Biol. 2009 Jun;258(3):455-64 19007794 , Abstract: Mitochondria play a central role in cellular energetic metabolism. The essential parts of this metabolism are the tricarboxylic acid (TCA) cycle, the respiratory chain and the adenosine triphosphate (ATP) synthesis machinery. Here a simplified model of these three metabolic components with a limited set of differential equations is presented. The existence of a steady state is demonstrated and results of numerical simulations are presented. The relevance of a simple model to represent actual in vivo behavior is discussed.