Researchers are developing a vaccine to protect horses against a disease caused by a bacterium. The vaccine contains a harmless molecule taken from the surface of the bacterium.
Which statement describes the role of the surface molecule in producing immunity?
It is recognised as foreign by white blood cells, which make antibodies with a matching shape.
It reproduces inside the horse's cells, causing a mild form of the disease.
It counteracts the toxins released by the bacterium, so the horse does not feel ill.
It kills any bacteria already in the horse's blood before they can reproduce.
252 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.