Infection & ResponseTopic Summary
Knowledge Organiser
Part of Human Defense Systems - Non-specific — GCSE Biology
This topic summary covers Knowledge Organiser within Human Defense Systems - Non-specific for GCSE Biology. Physical and chemical barriers, white blood cell responses, inflammatory response It is section 15 of 16 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 16
Practice
19 questions
Recall
22 flashcards
Knowledge Organiser
First Line of Defence
- Skin: physical barrier; skin oils help maintain barrier
- Mucus: traps pathogens in nose and airways
- Cilia: sweep mucus upward to the throat
- Stomach acid (pH ~2): kills ingested pathogens
- Lysozyme: destroys bacterial cell walls (in tears, saliva)
- Blood clots/scabs: seal wounds to prevent pathogen entry
Second Line of Defence
- Phagocytes: white blood cells that destroy pathogens
- Phagocytosis: detect → engulf → digest with enzymes
- Non-specific: same response to any pathogen
Common Marks Lost
- Saying mucus kills bacteria (it traps; lysozyme kills)
- Describing mucus without cilia (they work as a pair)
- Missing the digestion step in phagocytosis
- Not linking the barrier to HOW it prevents infection