Question

Antigen-binding site in an antibody is formed by the variable region of

• A. two light chains
• B. two heavy chains
• C. one heavy chain and one light chain
• D. only one light chain

Answer 1

The correct option is C one heavy chain and one light chain

Antibodies are proteins that bind to antigens that enter the body and help in eliminating them.

Each antibody (H₂L₂) is made up of two short light (L) peptide chains and two long heavy (H) peptide chains. These chains are joined to each other by disulfide bonds, and are arranged in a Y shaped structure.

Each chain in the antibody has two regions, constant (amino acid sequence and conformation remains the same in all antibodies) and variable (amino acid sequence and conformation varies from one antibody to another) regions.

The unique antigen-binding site in each antibody that is compatible with specific antigens is composed of the variable regions of one heavy and one light chain.


Figure : Antibody molecule