What type of biological molecule are antibodies?

Antibodies are specialized proteins produced by the immune system to identify and neutralize pathogens such as bacteria and viruses. They belong to a class of proteins known as immunoglobulins. The structure of an antibody consists of four polypeptide chains: two heavy chains and two light chains, which form a Y-shaped molecule. This structure allows antibodies to bind specifically to particular antigens, marking them for destruction or neutralization.

The roles that proteins play in the body are diverse, including structural support, transport, signaling, and as enzymes, but antibodies are specifically tailored for immune responses. Their ability to recognize and bind to specific antigens is crucial for the adaptive immune system, making them a fundamental component in providing immunity.

In contrast, carbohydrates primarily serve as energy sources and structural components, lipids are involved in storing energy and forming cell membranes, and nucleic acids (like DNA and RNA) are vital for genetic information storage and transmission. Each of these biomolecules has distinct functions within biological systems, further emphasizing that antibodies, being proteins, play a unique and critical role in immune defense.