The _____ of an Antibody Molecule Functions to Recognize and Bind

Question

The _____ of an antibody molecule functions to recognize and bind to a specific antigen.
A) antigen-antibody complex
B) antigen-binding site
C) light chain
D) heavy chain
E) immunoglobulin motif

Accepted Answer

The antigen-binding site (also known as paratope) is the region of the antibody molecule that specifically recognizes and binds to a unique part of an antigen molecule. The antibody molecule is composed of two heavy chains and two light chains, and it has two identical antigen-binding sites formed by the variable regions of these chains. Therefore, choices C, D, and E are incorrect as they refer to other structural parts of the antibody molecule that do not have a primary role in antigen recognition and binding. Choice A refers to the complex formed when the antigen binds to the antibody, which occurs after the initial recognition and binding step facilitated by the antigen-binding site.