A Level Biology Practice Exam

What is the role of the cell surface antigen?

1. To provide energy to the cell

2. To trigger cell division

3. To identify the cell for immune recognition

4. To synthesize proteins

The correct answer is: To identify the cell for immune recognition

Cell surface antigens play a crucial role in the immune system by acting as markers on the surface of cells, allowing the immune system to recognize and differentiate between self and non-self cells. This identification process is vital for the immune response, as it enables immune cells to recognize pathogens, such as bacteria and viruses, as well as infected or cancerous cells. Cell surface antigens are typically proteins or glycoproteins that are unique to individuals or specific to certain groups of organisms. When the immune system encounters these antigens, it can initiate an appropriate immune response, mobilizing various cells to attack and eliminate the perceived threat. This is central to processes such as the activation of T cells and the production of antibodies by B cells. While energy provision, cell division, and protein synthesis are critical cellular functions, they are not the primary roles of cell surface antigens. The specific function of identifying cells for immune recognition is what sets apart the role of cell surface antigens as crucial in maintaining the body's defense systems against infections and diseases.