What is the term for the process of building up molecules?

The term that describes the process of building up molecules is known as anabolism. Anabolism is a part of metabolism, which encompasses all biochemical reactions in the body. Specifically, anabolism refers to the constructive phase of metabolism where smaller molecules are synthesized into larger, more complex molecules, such as proteins from amino acids or glycogen from glucose.

This process is crucial for growth, repair, and maintenance of body tissues. During anabolism, energy is required to form these larger molecules, which differentiates it from catabolism, the breakdown of larger molecules into smaller components, often releasing energy. While metabolism includes both anabolic and catabolic processes, the specific focus on the building-up aspect aligns directly with the definition of anabolism. Decomposition typically refers to the breakdown of substances, which further establishes why anabolism is the correct choice in this context.