Catabolic Metabolism: the Synthesis of ATP

Metabolism may be defined as the total of all the chemical reactions that occur in organisms. Green plants can synthesize all the thousands of compounds they contain from carbon dioxide, water, and inorganic nutrients. The discussion of the complicated toP_ic of metabolism is somewhat simplified by separation of the subject into two areas—catabolic and anabolic metabolism. Catabolic metabolism is degradative and is generally exergonic. ATP is a product of catabolic metabolism. In contrast, anabolic metabolism is synthetic and requires ATP. Fortunately, there are relatively few major pathways of energy metabolism.