at whish level (secondary or primary) protein becomes functional?
Protein becomes functional when it folds into three-dimensional (tertiary structure) form. Primary structure is the sequence of amino acid residues. Secondary structure refers to particularly stable arrangements of amino acid residuesgiving rise to recurring structural patterns. Tertiary structure describes all aspects of thethree-dimensional folding of a polypeptide. When a protein has two or more polypeptide subunits, theirarrangement in space is referred to as quaternary structure. Primary structure determines tertiarystructure, and tertiary structure determines function.