How many water molecules would be produced in making a polypeptide that is 14 amino acids long?

13, one less than the amino acids in the polypeptide. Polypeptides are chains of amino acids linked together that make up proteins. The amino acids in the polypeptide are joined to each other by a peptide bond. A peptide bond is a bond formed between the amino group of an Amino acid and the carboxylic group of another amino acid with release of one water molecule.

13 Amino acids have a common structure where there is a carboxyl group at one end (CO2H) and a amino group at the other (NH2). There's also a side chain that's unique for every amino acid. When two amino acids are joined in producing a polypeptide, the carboxyl and amino groups are linked with the release of a water molecule. So in this problem, you simply need to count the number of links, which will be 1 less than the number of amino acids in the chain. Hence, for a 14 amino acid chain, you need 13 links which produced 13 water molecules.