Final answer:
Polypeptides are synthesized from amino acids, where the amino group of one amino acid bonds with the carboxyl group of another, forming a peptide bond and releasing water, in a process catalyzed by ribosomes. The resulting polypeptide chains can fold to become functional proteins after post-translational modifications.
Step-by-step explanation:
Polypeptides are assembled from amino acids. Each amino acid has an amino group (NH2) and a carboxyl group (COOH). When amino acids combine, the amino group of one amino acid forms a peptide bond with the carboxyl group of another, releasing a molecule of water. This reaction is catalyzed by ribosomes in a process called dehydration synthesis. As amino acids continue to link, a polypeptide chain forms, with an N terminal at one end and a C terminal at the other. These polypeptides can then fold into distinct shapes to form proteins, which become fully functional after post-translational modifications such as cleavage or phosphorylation.