A student catches influenza. Describe how the student's immune system responds to destroy the influenza virus once it has entered the body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
White blood cells recognise the influenza virus through receptors that bind to viral antigens. Lymphocytes then produce antibodies that are complementary to those antigens. The antibodies bind to the virus, causing agglutination and neutralisation. Phagocytes such as macrophages engulf and digest the virus via phagocytosis. After the infection, memory cells persist, allowing a faster antibody response if the virus re‑enters the body.
Examiner tips
- Use the term ‘antigens’ and ‘antibodies’ – examiners look for specific vocabulary.
- Show the sequence: detection → antibody production → neutralisation → phagocytosis → memory.
- Keep the answer concise – 5 marks, so one sentence per point is enough.
- Mention ‘memory cells’ to secure the last mark.
Common mistakes
- Confusing antibodies with T‑cell receptors; only B‑cell antibodies bind antigens.
- Forgetting to state that antibodies cause agglutination or neutralisation.
- Using vague terms like ‘immune cells’ instead of specifying white blood cells, lymphocytes, phagocytes.
Mark scheme (5 marks)
- White blood cells detect the influenza virus using receptors on their cell surface to identify antigens on the pathogen.
- Lymphocytes release antibodies that are specific / complementary to the antigens on the influenza virus.
- Antibodies bind to the antigens on the virus / clump the virus particles together (agglutination) to neutralise the pathogen.
- Phagocytes engulf / ingest and digest the pathogen / virus using enzymes (phagocytosis).
- Memory cells remain after the infection so that if the influenza virus enters the body again, antibodies are produced more quickly.
Related
- All Eduqas A-Level Biology revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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