Final answer:
Polypeptides are assembled from amino acids through peptide bond formation. They are formed when the amino group of one amino acid reacts with the carboxyl group of another amino acid. Polypeptides can undergo post-translational modifications to become functional proteins.
Step-by-step explanation:
Polypeptides are assembled from amino acids. A polypeptide is technically a polymer of amino acids, and it is formed when the amino group of one amino acid forms a peptide bond with the carboxyl group of another amino acid. These peptide bonds are catalyzed by ribosomes and generate one water molecule. The resulting chain of amino acids is known as a polypeptide, which can have a variable length and may undergo post-translational modifications to become a functional protein.