Which specific structure on an antigen is recognized and bound by antibodies?

• A. Epitope
• B. Paratope
• C. Isotype
• D. Hapten

Answer: (A)

Verified step by step guidance

1. Understand that antibodies recognize and bind to specific parts of an antigen, which are called epitopes.
2. Recall that an epitope is the precise molecular structure or region on the antigen that is recognized by the antibody.
3. Differentiate between the terms: the paratope is the part of the antibody that binds the epitope, not the antigen structure itself.
4. Isotype refers to the class of antibody (e.g., IgG, IgM), not the antigen structure.
5. Hapten is a small molecule that can elicit an immune response only when attached to a larger carrier, and is not the specific structure recognized on an antigen.