The primary function of an antibody has been fulfilled when it
A) crosses the placenta.
B) binds an antigenic determinant.
C) attaches to a mast cell.
D) activates the kinin system.
E) activates complement.

Question

Quizplus · Accepted Answer

The primary function of an antibody is to bind to an antigenic determinant, also known as an epitope, on an antigen molecule. This binding allows the antibody to mark the antigen for destruction by other immune system components.

Options A, C, D, and E are not the primary function of an antibody. While antibodies can cross the placenta (Option A) and attach to mast cells (Option C), these are secondary functions. Activating the kinin system (Option D) is not a function of antibodies, and while antibodies can activate complement (Option E), this is also a secondary function.

The Primary Function of an Antibody Has Been Fulfilled When