What are formed when amino acids react by condensation polymerisation?

When amino acids undergo condensation polymerisation, they form polypeptides. This process involves the removal of a water molecule during the reaction between the amino group of one amino acid and the carboxyl group of another. As the amino acids link together through peptide bonds, a chain of amino acids, or a polypeptide, is created.

Polypeptides can consist of varying numbers of amino acids, and they may fold into specific shapes to perform various biological functions. If a polypeptide achieves a specific structure and functional configuration, it can be referred to as a protein.

The other options represent different biomolecules: fatty acids are components of lipids, nucleotides are the building blocks of nucleic acids like DNA and RNA, and while proteins can be formed from polypeptides, the immediate product of the condensation polymerisation of amino acids is specifically polypeptides.