Which term describes a peptide containing a chain of more than 10 amino acids?

A peptide that consists of a chain of more than 10 amino acids is correctly described as a polypeptide. Polypeptides are essentially longer chains that can be formed through the polymerization of amino acids, which are the building blocks of proteins. While a protein is typically a larger, functionally active molecule comprised of one or more polypeptide chains folded into a specific three-dimensional shape, the term "polypeptide" specifically refers to the chain itself before it becomes a fully functional protein.

In contrast, the other terms provided do not accurately represent a chain of more than 10 amino acids. A triglyceride is a type of lipid comprised of glycerol and three fatty acids, unrelated to amino acids. The term monomer refers to a single molecule that can join together with others to form a polymer, such as an amino acid which, when linked, can form polypeptides and proteins. Therefore, polypeptide is the appropriate term to describe a chain composed of over 10 amino acids.