Assessment And Qualifications Alliance (AQA) GCSE Biology Paper 1 Practice Exam

The primary action of T-lymphocytes in the immune response is to recognize and destroy infected cells. T-lymphocytes, or T-cells, play a critical role in cell-mediated immunity. They can directly target and eliminate cells that have been infected by pathogens, such as viruses. This function is vital for controlling infections and preventing the spread of pathogens within the body. T-cells are equipped with receptors that allow them to identify infected cells displaying specific antigens on their surface. Once they recognize these antigens, they bind to the infected cells and can initiate a series of actions that lead to the destruction of the infected cells. This process is essential for maintaining the body’s health and preventing disease. The other options involve different functions primarily associated with other components of the immune system. Antibodies are produced by B-lymphocytes, histamines are released during allergic responses and inflammation, and antitoxins can be produced by plasma cells which are derived from B-cells. Thus, option D accurately captures the primary role of T-lymphocytes in the immune response.