They expose your immune system to a harmless form of the pathogen so memory cells form, allowing rapid response if exposed later. Learn it step by step →
Immunity & Disease is a core part of A-Level Biology. Revise the key concepts and common mistakes below, then lock them in with the free games.
Key concepts
Active immunityBody makes its own antibodies — slow but long-lasting
Passive immunityAntibodies received from another source — fast but short-lived
VaccineDose of antigen (dead/attenuated/subunit) triggering active immunity
Questions where students often pick the tempting wrong answer — make sure you know the right one:
How do vaccines protect you from a disease?✗ Vaccines kill the pathogen if it ever enters the body.✓ They expose your immune system to a harmless form of the pathogen so memory cells form, allowing rapid response if exposed later.
Why is the secondary immune response to a pathogen faster and stronger than the primary?✗ The pathogen becomes weaker after the primary exposure, so the body has an easier job.✓ Memory cells generated during the primary response can rapidly proliferate and produce large amounts of specific antibody on re-exposure.
What is actually transferred to the body when you get a vaccine?✗ Vaccines inject ready-made antibodies directly into the bloodstream.✓ Antigens (often from weakened, dead, or fragmented pathogens) that train the immune system to make memory cells.
How do bacteria become resistant to an antibiotic?✗ They learn to resist✓ Random mutations conferring resistance are selected for
What is the main role of B-cells compared to T-cells?✗ B-cells and T-cells both produce antibodies in equal amounts.✓ B-cells produce antibodies (humoral response); T-cells coordinate the immune response and kill infected cells (cell-mediated response).
Practise Immunity & Disease — free games
Test yourself with these quick revision games for this topic:
