Explain the structure of antibodies.

The structure of an antibody is similar to the alphabet Y. It has two heavy chain, each containing 440 Amino acids, and two light chains , containing 220 amino acids each. One heavy and one light chains join by disulphide bonds to form a dimer. Two such dimers form equal halves of the antibody structure. Both these dimers are joined to each other by disulphide bonds‌. Each heavy and light chain has two zones,

1. Variable region, also called the Fab part, is present near the amino end. It interacts with the antigen.

2. Constant region, also called the Fc part, is present near the carboxy end . It contains the hinge and allows accommodation of large molecule of antigen.