They are linear polymers of a-amino acids.
(a) Primary structure: It simply reveals the sequence of amino
acids.(fatty acids , starch)
(b) Secondary structure: α-helix structure maintained by hydrogen
bonds or β-pleated sheet structure when R is
Tertiary structure: The folding and
superimposition of polypeptide chains forms
a compact globular shape, termed as tertiary structure. It is stabilised by
covalent, ionic, hydrogen and disulphide bonds. The precise arrangement
constitutes the quaternary structure.