The First Step in a B-Cell's Defense Against a Microorganism

Question

The first step in a B-cell's defense against a microorganism is to
A)recognize the antigen.
B)bind to the antigen.
C)secret antibodies.
D)undergo mitosis.

Accepted Answer

The first step in a B-cell's defense against a microorganism is to recognize the antigen. B-cells have a specific receptor on their surface called the B-cell receptor (BCR) that can bind to a specific antigen. Once the B-cell recognizes the antigen, it can then begin the process of activating and producing antibodies. Binding to the antigen (choice B) is a subsequent step that occurs after recognition. Secretion of antibodies (choice C) is also a later step in the process. While mitosis (choice D) may occur as a result of B-cell activation, it is not the first step in the defense against a microorganism.