What is the individual "building block" or unit that makes up a polymer?

The individual "building block" or unit that makes up a polymer is referred to as a monomer. Polymers are large molecules composed of repeating structural units, known specifically as monomers. These monomers are connected through chemical bonds in a process called polymerization. Each type of polymer is made from different types of monomers, which dictate the properties and functions of the resulting polymer.

For instance, proteins are polymers made from amino acids (the monomers), and nucleic acids (like DNA and RNA) are polymers formed from nucleotide monomers. Understanding the distinction between monomers and polymers is crucial in the study of biochemistry and biology because it relates directly to how complex biological structures are formed and function within living organisms.