The structure of the protein that is absolutely necessary for its biological activity is

Step-by-step solution

In tertiary structure, the polypeptide chain having secondary structure is twisted and folded to produce a stable, three dimensional structure, which may be maintained by three types of bonds e.g. ionic bond, hydrogen bond and disulphide bond. In a large protein like hemoglobin, or in the case of an enzyme, the molecule undergoes further folding and coiling to attain functional conformation and is termed as the tertiary structure. The coils and folds of the protein molecule are so arranged as to hide non-polar amin