Which term is used to describe the basic building block of proteins?

The basic building block of proteins is referred to as a monomer, specifically amino acids. Amino acids are small organic molecules that contain both an amino group and a carboxyl group, along with a side chain that is specific to each amino acid. When amino acids link together through peptide bonds, they form polypeptides and ultimately proteins. This process is fundamental to the structure and function of proteins, as the order and specific types of amino acids determine the protein's unique properties and biological activity.

In contrast, polymers are large molecules made up of repeating subunits, which can include proteins but also other macromolecules like polysaccharides and nucleic acids. Enzymes are a specific type of protein that acts as catalysts to speed up biochemical reactions, but they are not the building blocks of proteins themselves. Carbohydrates are a different class of biomolecules, primarily composed of sugar units, and do not directly relate to the structure of proteins.