Question

Place the following events in activation of a B cell by a microbe in the order in which they would occur.

Several rounds of division occur, producing many B cells that all express the same B cell receptor.
A B cell differentiates from a lymphocyte stem cell, and the mature B cell expresses a specific type of B cell receptor on its cell membrane.
The B cell's BCR (B cell receptor) binds to a foreign antigen with high specificity and high affinity.
Second messenger signaling is activated in the B cell.
Gene expression is altered in the B cell, and the B cell begins to divide.

Answer 1

The activation process of a B cell by a microbe includes differentiation from a lymphocyte stem cell, antigen binding by the B cell receptor, activation of signaling pathways, alteration of gene expression, and rounds of division producing B cells with identical receptors.

Step-by-step explanation:

The activation of a B cell by a microbe involves a series of steps which must occur in a specific order for effective immune response. Listing these steps in the correct sequence provides a clear understanding of B cell activation:

1. A B cell differentiates from a lymphocyte stem cell, and the mature B cell expresses a specific type of B cell receptor on its cell membrane.
2. The B cell's BCR (B cell receptor) binds to a foreign antigen with high specificity and high affinity.
3. Second messenger signaling is activated in the B cell.
4. Gene expression is altered in the B cell, and the B cell begins to divide.
5. Several rounds of division occur, producing many B cells that all express the same B cell receptor.

These steps are critical for the body's adaptive immune system to mount a specific response against the antigen presented by the microbe. The ultimate goal of these steps is the production of plasma cells and memory B cells that can produce antibodies specific to the antigen and protect the host from future infections by the same pathogen.

Answer 2

The proper order is as follows-

1) A B cell differentiates from a lymphocyte stem cell, and the mature B cell expresses a specific type of B cell receptor on its cell membrane.

2) Gene expression is altered in the B cell, and the B cell begins to divide.

3) Several rounds of division occur, producing many B cells that all express the same B cell receptor.

4) The B cell's BCR (B cell receptor) binds to a foreign antigen with high specificity and high affinity.

5) Second messenger signaling is activated in the B cell.