A Level Biology Practice Exam

Which of the following is NOT a characteristic of specific immunity?

1. Memory of antigens

2. Greater response upon re-exposure

3. Immediate response to all pathogens

4. Activation by the presence of antigens

The correct answer is: Immediate response to all pathogens

Specific immunity is characterized by its ability to recognize and remember specific antigens, leading to a tailored immune response. One of its key features is that it has a memory component, which allows the immune system to recognize previously encountered pathogens quickly and mount a stronger response upon re-exposure. This is evident in the greater response to a pathogen upon subsequent encounters. The activation of specific immunity is initiated by the presence of antigens, which are unique molecules found on pathogens. When these antigens are detected, the immune system activates B cells and T cells that can specifically target those antigens, leading to a precise immune response. Immediate responses to all pathogens, however, are characteristic of innate immunity, not specific immunity. Innate immunity provides a rapid, general defense against pathogens that does not involve the specialized recognition of specific antigens. In contrast, specific immunity takes time to develop as it requires the activation and proliferation of specific immune cells targeted towards the antigen. This distinction is crucial for understanding how the immune system operates in both immediate and adaptive contexts.