Which statement about antibodies is correct?

• A. All antibodies are immunoglobulins
• B. Antibodies are lipids
• C. Antibodies are carbohydrates
• D. Antibodies are nucleic acids

Answer: (A)

Antibodies are proteins produced by plasma cells that specifically recognize antigens. Every antibody is an immunoglobulin, meaning it belongs to the immunoglobulin family. This class is defined by its protein structure, built from heavy and light chains, with variable regions that determine what antigen it binds and a constant region that helps recruit other parts of the immune system. Because of this protein, immunoglobulin nature, the statement that all antibodies are immunoglobulins is correct. Antibodies are not lipids, carbohydrates, or nucleic acids—their fundamental makeup is amino acids forming a protein. They may have carbohydrate groups attached, but that doesn’t change their core identity as immunoglobulin proteins.