Specific immune responseEdexcel International A Level Biology: Flashcards

Exam questions on Specific immune response

1. A patient is infected with a bacterium that carries a protein on its cell surface membrane which the patient's immune system has not met before. Within days the patient's blood contains proteins that bind only to this bacterial protein and to no other molecule.
   Explain why these proteins bind only to this bacterial protein.2 marks
2. A student is infected with a virus for the first time. Antibodies against the virus appear in her blood after about ten days and reach a modest concentration. Several months later she is exposed to the same virus again. Within two days the antibody concentration in her blood is much higher than before, and she does not become ill.
   Explain why the antibody concentration rises faster during the second exposure to the virus.2 marks
3. A patient has a very low count of T helper cells. He suffers frequent severe infections, and he also produces much less antibody than a healthy person after exposure to a new pathogen.
   Explain how T helper cells normally enable B cells to produce antibodies.3 marks