CHAPTER 8 An Introduction to Metabolism Metabolism is the totality of an organism?s chemical reactions Manage the materials and energy resources of a cell Catabolic pathways release energy by breaking down complex molecules into simpler compounds Eg. digestive enzymes break down food ? release energy Anabolic pathways consume energy to build complex molecules from simpler ones Eg. amino acids link to form muscle protein ENERGY = CAPACITY TO DO WORK Kinetic energy (KE): energy associated with motion Heat (thermal energy) is KE associated with random movement of atoms or molecules Potential energy (PE): stored energy as a result of its position or structure Chemical energy is PE available for release in a chemical reaction Energy can be converted from one form to another