Quaternary structure, occurs when two or more polypeptide chains interact through disulfide bonds, dispersion forces,
salt bridges, or hydrogen bonds. The intact protein may be called a dimer (2), trimer (3), tetramer (4), pentamer (5), or
hexamer (6), depending on the number of polypeptide chains involved.
Insulin is self-administered as an injection. Select the reasons why insulin is not taken orally.
Enzymes in the stomach would destroy the insulin by cleaving it into small pieces.
The environment of the stomach would alter the primary structure of insulin.
The pH of the stomach would cause the insulin to become denatured.
Insulin is secreted by the pancreas and does not normally pass through the stomach.
