A veterinary team monitored the antibody response of captive-bred cranes to a vaccine. The first injection caused a slow increase in antibody concentration. After a second injection of the same vaccine, antibody concentration increased much more quickly.
Why did the antibody concentration increase more quickly after the second injection?
Antibodies formed after the first injection divided when they encountered the antigens again
White blood cells engulfed the vaccine antigens and then released them as antibodies
Antigens in the second injection were converted directly into antibodies in the blood
Memory cells formed after the first injection recognised the antigens and quickly produced antibodies
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.