VerifiedHint: The antigen binds to the antigen-binding site of the antibody which contains the variable domain from both the chains.
Complete answer:
An Antibody is a Y-shaped structure that helps the immune system to fight against antigens (any foreign material that enters inside a human body). It is made up of a variable and a constant region. Each antibody consists of an antigen-binding site which helps the antibody to bind to the antigen. This antigen binding site is composed of a variable domain of heavy chain and the variable domain of light chain. Due to this, the antigen-binding site of an antibody is located between one heavy chain and one light chain.
Antigen binding sites have high amino-acid sequence diversity within the variable regions of antibody and T-cell receptor and they correspond to the localized region of the antibody and T-cell receptor chains that are responsible for determining antigenic specificity and binding to the antigen. The epitope of antigen binds to the antibody at the antigen-binding site by noncovalent forces like electrostatic forces, Hydrogen bonds, hydrophobic forces, etc.
During the antigen-antibody binding, the hinge region in an antibody facilitates better binding between the antibody and epitope of an antigen. Once the antibody binds with antigen, they neutralize and destroy them. Antibodies are highly specific to an antigen-based upon their structure.
Additional information:
> Antibodies are also known as Immunoglobulins. They are approximately 150 kilodaltons (kDa) in size. They constitute two heavy chains and two light chains which are held are held together with the help of disulfide bonds.
> Each heavy and light chain consists of a variable region with 100 to 100 amino acids which differs with a different type of antibody and a constant region. Antibodies are of five types: Immunoglobulin A, Immunoglobulin M, Immunoglobulin G, Immunoglobulin D, Immunoglobulin E.
So, the correct option is C.
Note: The epitope of the antigen binds to the antibody at the antigen-binding site which triggers the immune response.
