Antigens and phagocytosisAQA A-Level Biology: Mind map

Exam questions on Antigens and phagocytosis

1. Influenza viruses carry two types of glycoprotein on their surface, haemagglutinin and neuraminidase. The genes coding for these proteins mutate frequently. Every year public health scientists predict which strains will be common and a new seasonal influenza vaccine is produced.
   Explain why a new influenza vaccine has to be produced each year.2 marks
2. A patient with kidney failure receives a kidney from an unrelated donor. Without drugs that suppress the immune system, the patient's immune system would attack the transplanted kidney.
   Explain why finding a donor with a very close tissue match reduces the risk of the kidney being rejected.2 marks
3. Neutrophils, a type of phagocyte, were mixed with Staphylococcus aureus bacteria and viewed under a microscope. After a few minutes bacteria could be seen inside membrane-bound vacuoles in the neutrophils. A rare inherited condition causes a patient's neutrophils to engulf bacteria normally, but the bacteria survive inside the neutrophils and the patient suffers repeated infections.
   Describe how a neutrophil ingests and destroys a bacterium.3 marks