Anabolism refers to metabolic pathways that:

• A. Metabolic pathways that break down molecules, releasing energy.
• B. A measure of disorder or randomness.
• C. Metabolic pathways that construct molecules, requiring energy.
• D. Measures the portion of a system's energy that can perform work.

Answer: (C)

Anabolism is the biosynthetic side of metabolism: it builds larger, more complex molecules from smaller precursors. These reactions require energy input because forming chemical bonds and increasing molecular order costs energy, usually supplied by carriers like ATP or NADPH. Examples include making proteins from amino acids, synthesizing nucleic acids, and assembling polysaccharides like glycogen.

This contrasts with pathways that break down molecules to release energy, which is why the idea of breaking down substances would not describe anabolism. The notion of disorder or entropy isn’t a description of a metabolic pathway type, and a general measure of energy available to do work refers to thermodynamics rather than the specific process of biosynthesis.