What are large molecules made up of small monomers called?

The large molecules made up of small monomers are called macromolecules.

Explanation:

In biochemistry macromolecules are the complex molecules that are formed by the polymerization of simple monmeric subunits.

For example

Polysaccharides are formed by the joining monosaccharides by glycosidic linkages.

Protein or polypeptides are formed by the joining of amino acids by peptide bonds.

Lipids are composed of fatty acid monomers

Nucleic acid such as DNA and RNA are formed by the joined of their monomeric subunits a; so called nucleotides by phosphodiester linkage.