BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Insulin is a small globular protein containing two chains, A (21 residues) and B (30 residues) (Fig. 2.1A). Stored in the cell as a Zn2+-stabilized hexamer, the hormone dissociates in the bloodstream to function as a Zn2+-free monomer (Fig. 2.1B).

Detailed explanation-2: -Haemoglobin is an example of globular protein. It carries oxygen in the blood.

Detailed explanation-3: -Insulin and Albumin are the common fibrous proteins.

Detailed explanation-4: -Primary structure. The simplest level of protein structure, primary structure, is simply the sequence of amino acids in a polypeptide chain. For example, the hormone insulin has two polypeptide chains, A and B, shown in diagram below.

Detailed explanation-5: -Surrounding its core, the monomer has two extensive nonpolar surfaces. One of them is a flat one that is aromatic and gets buried when there is a dimer formation. The other surface is more extensive and disappears when a hexamer is formed. This is called the quaternary structure of insulin.