Polypeptide formation in amino acid is by:

Ans. A. Primary structurePrimary structureIt is the linear sequence of amino acid held together by peptide bonds in its peptide chains. Bond involved in primary structure is Peptide Bond, a type of covalent bond.Secondary StructureConfigurational relationship between residues which are about 3-4 amino Acids apart in linear sequence.The folding of short (3- to 30-residue), contiguous segments of polypeptide into geometrically ordered unitsTertiary structureThe entire three-dimensional conformation of a polypeptide is referred to as tertiary structure.Quaternary structureIf more than one polypeptides aggregate to form one functional protein, the spatial relationship between the polypeptide subunits is referred to as Quaternary structure.