Define the following as related to proteins:
i) Peptide linkage ii) Primary structure iii) Denaturation

i) The linkage (—CO—NH—) which unites various amino acid units in peptide molecule is called peptide linkage.

ii) Primary structure: The sequence of amino acids in a protein molecule is called the primary structure of protein. Different chemical and biological functions are due to the variation in primary structure.
iii) Denaturation: The process of losing biological activity and helical structure of proteins (or) polypeptide by disturbing Hydrogen bonds by varying temperature or chemical change (change in pH) is called denaturation.