<prompt> A single immunoglobulin molecule contains -1 light chain, 1 heavy c hain2 heavy chains, 1 light2 light chains, 2 heavy chains2 light chains, 1 heavy chain  <response>: They are typically made of basic structural units--each with two large heavy chains and two small light chains. Ref: Ananthanarayan Parkers textbook of microbiology 9th edition pg: 94 