Question

Each immunoglobin has two heavy chains and two light chains, the antigen binding is present in

• A. variable region of heavy chain
• B. variable region of both heavy and light chain
• C. variable region of light chain
• D. constant region of both light and heavy chain

Answer 1

Answer: (B)

Each immunoglobulin molecule is made up to $4$-polypeptide chains. These are two long chains, called heavy or $H$-chains and two short chains, called light or $L$-chams. The four polypeptide chains are held together to form a $Y$-shaped molecule. The two tips of this$Y$ shaped molecule bind to the specific antigen in a lock and key fashion. This leads to formation of antigen-antibody complex.