Infection & ResponseTopic Summary

Knowledge Organiser

Part of Adaptive Immunity and Antibodies · GCSE GCSE Biology revision

This topic summary covers Knowledge Organiser within Adaptive Immunity and Antibodies for GCSE Biology. Specific immune responses, antibody production, lymphocytes, memory cells It is section 15 of 15 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 15 of 15

Practice

20 questions

Recall

25 flashcards

Knowledge Organiser

Key Cells
  • B lymphocyte — recognises antigen, divides, forms plasma cells and memory B cells
  • Plasma cell — secretes thousands of antibodies per second specific to one antigen
  • Memory B cell — long-lived, enables fast secondary response
  • Helper T cell — coordinates immune response, activates B cells
  • Killer T cell — directly destroys infected body cells
Key Processes
  • Clonal selection — antigen selects specific B cell with matching receptor shape
  • Clonal expansion — selected B cell divides repeatedly
  • Antibody production — plasma cells secrete specific antibodies
  • Primary response — slow (5–10 days), low antibody levels, creates memory cells
  • Secondary response — fast (1–3 days), high antibody levels, prevents disease
Common Marks Lost
  • Saying antibodies kill pathogens (they tag them for phagocytes — phagocytes do the killing)
  • Confusing plasma cells (make antibodies now) with memory cells (future protection)
  • Saying secondary response is slower (it is much faster — 1–3 days vs 5–10 days)
  • Not explaining WHY secondary response is faster (memory cells already present with correct receptor shape)
  • Saying all white blood cells make antibodies (only B lymphocytes / plasma cells produce antibodies)
Key Terms
  • Antigen — foreign molecule (usually protein on pathogen surface) that triggers immune response
  • Antibody — specific Y-shaped protein produced by plasma cells that binds to one antigen
  • Antitoxin — antibody that binds to and neutralises a bacterial toxin
  • Clonal expansion — activated B cell divides rapidly to produce many identical daughter cells
  • Immunological memory — memory B cells persist for years, enabling faster secondary response on re-exposure

Revise this topic interactively on PrepWise — self-test mode, tap-to-reveal definitions, and Common Mistakes from examiners.

Try the interactive Knowledge Organiser — free →

Keep building this topic

Read this section alongside the surrounding pages in Adaptive Immunity and Antibodies. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Adaptive Immunity and Antibodies

What are antigens?

  • A. Antibodies produced by white blood cells
  • B. Unique proteins on the surface of pathogens
  • C. Toxins produced by bacteria
  • D. Memory cells that remain after infection
1 markfoundation

Explain how lymphocytes produce antibodies to destroy a specific pathogen.

3 marksstandard

Quick Recall Flashcards

What is an antigen?
A protein on the surface of a pathogen (or cell) that the immune system recognises as foreign. Antigens trigger the body to produce antibodies.
What is an antibody?
A protein produced by lymphocytes (white blood cells) that binds to a specific antigen. Each antibody has a unique shape that fits one antigen only — like a lock and key.

20 questions on Adaptive Immunity and Antibodies — practise free

Instant marking, adaptive difficulty, and 25 spaced repetition flashcards. Free until your GCSEs.

Try PrepWise Free