What You Need to Know

Key Concept Diagram

The immune system has two lines of defence: innate (non-specific, fast) and adaptive (specific, slower but memorises)

B lymphocytes produce antibodies that neutralise specific pathogens; T cells kill infected cells

Immunological memory: after first exposure, memory cells remain — enabling rapid response upon re-exposure

Vaccines use antigens (weakened/killed pathogens, subunits, or mRNA) to generate immunity without causing disease

Key Vocabulary

antibody

A protein produced by B cells that specifically binds to and neutralises a pathogen

antigen

A molecule (usually on a pathogen's surface) that triggers an immune response

immunological memory

The ability of the immune system to respond faster and more effectively upon repeated exposure to the same pathogen

mRNA vaccine

A vaccine that delivers messenger RNA instructions for cells to produce an antigen, triggering an immune response

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

Which cells produce antibodies?

T lymphocytes B lymphocytes Red blood cells Macrophages only

Question 2

How does a vaccine prevent disease?

By killing all bacteria in the body By boosting general health and nutrition By triggering an immune response and creating immunological memory without causing disease By permanently altering your DNA

Question 3

What is immunological memory?

The brain's ability to remember past illnesses The ability to be immune to all diseases A type of vaccine technology The immune system's ability to respond faster and stronger upon repeated exposure to the same antigen

Question 4

mRNA vaccines (like COVID-19 vaccines) work by:

Delivering genetic instructions for cells to produce an antigen, which triggers immunity Injecting a weakened virus Permanently modifying human DNA Injecting antibodies directly into the bloodstream

Question 5

Which of the following contributes to "herd immunity"?

Only unvaccinated people having natural immunity A sufficient proportion of the population being immune (through vaccination or previous infection) to limit disease spread Every single person in a population being vaccinated Using antibiotics to prevent viral spread

Immunology & Vaccines