A Level Biology Practice Exam

What is the role of B effector cells in the immune system?

1. To produce antibodies only

2. To kill pathogenic cells directly

3. To divide and form plasma cell clones

4. To provide permanent immunological memory

The correct answer is: To divide and form plasma cell clones

B effector cells, also known as B effector or plasma cells, play a crucial role in the immune response by dividing and forming clones that produce large quantities of antibodies. When naive B cells encounter their specific antigen, they become activated and undergo clonal expansion. This process leads to the formation of plasma cells that secrete antibodies specific to the antigen they have recognized. Antibodies are essential for marking pathogens for destruction, neutralizing toxins, and facilitating their removal by other immune components. While it is true that B effector cells are involved in antibody production, the focus of the correct answer highlights their role in clonal expansion. The ability to clone and generate numerous plasma cells ensures that there is a sufficient supply of antibodies to combat an infection effectively. This amplification of the response is vital in providing a robust defense against pathogens. The other options refer to different roles and mechanisms within the immune system, which are not directly the function of B effector cells. For instance, while antibodies are produced by plasma cells, the singular focus on "producing antibodies only" underestimates the significance of their clonal expansion aspect. Additionally, B effector cells do not directly kill pathogenic cells, as that function is primarily carried out by cytotoxic T cells