The organic molecule composed of long chains of amino acids is a protein.

Here's why:

* Amino Acids: These are the building blocks of proteins. Each amino acid has a central carbon atom bonded to an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a unique side chain (R group).

* Polypeptide Chains: Amino acids link together to form chains called polypeptides. The bond between amino acids is called a peptide bond.

* Proteins: Proteins are large, complex molecules made up of one or more polypeptide chains. These chains fold into specific three-dimensional structures, which determine the protein's function.

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