Energy Metabolism

This article describes the processes of cellular respiration by which macronutrients are metabolized within cells to produce energy. The three principal stages of cellular respiration of glucose are outlined: glycolysis, the tricarboxylic acid (TCA) cycle, the electron-transfer chain and the resulting oxidative phosphorylation of adenosine diphosphate to adenosine triphosphate (ATP), a universal energy carrier. The processes by which fats and proteins are metabolized into substrates for cellular respiration and their relative importance in specific metabolic pathways is described. Energy required for growth and maintenance of living organisms is acquired through the cellular respiration of organic compounds from the food we eat.