A Level Biology Practice Exam

What role do lymphocytes play in the body?

1. They transport nutrients through the bloodstream

2. They assist in digestion

3. They are involved in the specific immune system

4. They absorb excess tissue fluid

The correct answer is: They are involved in the specific immune system

Lymphocytes play a crucial role in the specific immune system, which is part of the body's adaptive immune response. These white blood cells are primarily responsible for identifying and responding to specific pathogens, such as viruses and bacteria, that invade the body. There are several types of lymphocytes, including B cells and T cells, each with distinct functions. B cells produce antibodies that bind to antigens on the surface of pathogens, neutralizing them and marking them for destruction by other immune cells. T cells, on the other hand, come in various forms, such as helper T cells, which assist in orchestrating the immune response, and cytotoxic T cells, which directly attack and destroy infected cells. This specificity and ability to remember past infections allow lymphocytes to provide long-term immunity, making them fundamental to the immune system's function. In contrast, the other choices describe functions that are not related to the role of lymphocytes. Nutrient transport through the bloodstream is primarily carried out by red blood cells and plasma proteins. Digestion involves various organs and enzymes, rather than lymphocytes. Lastly, while lymphatic capillaries do absorb excess tissue fluid to maintain fluid balance in the body, this function is distinct from the immune activities performed by lymphocytes.