A. Enzymes make metabolic reactions happen faster. B. Metabolism is the controlled capacity to acquire and use energy. C. Two laws govern energy transformations. The Nature of Metabolism A. Energy Changes in Metabolic Reactions 1. Exergonic reactions result in products with less energy than the reactants had.
Endergonic reactions result in products with more energy than the reactants had.
B. Metabolic Pathways 1. In biosynthetic pathways, small molecules are assembled into large molecules-for example, simple sugars are assembled into complex carbohydrates. In degradative pathways, large molecules such as carbohydrates, lipids, and proteins are broken down to form products of lower energy. Released energy can be used for cellular work. Enzymes A. Characteristics of Enzymes 1.