Which one of the following statements best describes immunoglobulin structure?

Following is a schematic figure of Ig. Note that each peptide chain is drawn as a continuous line and attachments between heavy and light chains are noted by solid bars. There appears to be considerable flexibility in the hinge region between the Fc and the two Fab poions of the molecule. This allows the molecule to assume either a T shape or a Y shape. Myeloma proteins have been widely used for Ig structural studies. The basic immunoglobulin structure.The unit consists of two identical light polypeptide chains and two identical heavy polypeptide chains linked together by disulphide bonds Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition .