The primary structure of a protein refers to: (A) Linear structure and order of the amino acids present, (B) Regular confirmational forms of a protein, (C) Complete three-dimensional structure of the polypeptide units of a given protein, (D) Subunit structure of the protein
Answer is A. The linear sequence of amino acid residues and location of disulphide bridges, if any, in a polypeptide constitute its primary structure.