Which term describes the smallest building blocks used to construct macromolecules?

The smallest building blocks used to construct macromolecules are best described by the term "monomers." Monomers are single, small molecules that can join together in various arrangements to form larger and more complex structures known as polymers. Each type of macromolecule—such as proteins, nucleic acids, carbohydrates, and lipids—has specific monomers that make them up. For instance, amino acids are the monomers that combine to form proteins, while nucleotides serve as the monomers for nucleic acids like DNA and RNA.

While polymers signify the large molecules formed by the repetitive linkage of monomers, oligomers refer to small chains of monomers that are fewer in number than those forming a full polymer but still larger than a single monomer. Amino acids function as individual units within the larger category of monomers, specifically relating to proteins. Therefore, the term monomers precisely captures the essence of the smallest distinct units that serve as the foundational components of macromolecular structures.