Non-specific defences 0.0 / 5 ? BiologyHuman non-specific defences and plant defencesGCSEOCR Created by: A-haCreated on: 18-11-19 18:38 Key words Non-specific defences- defences that are always present 1 of 7 Non-specific defences in humansPHYSICAL 1) Physical Respiratory tract Lined with mucus Mucus traps particles Cilia wafts the mucus up to the back of the throat to be swallowed Skin Barrier Platelets Clot blood Blood clotting stops you from loosing too much blood and prevents microorganisms from entering the blood 2 of 7 Non-specific defences in humansCHEMICAL 2) Chemical Eyes enzyme called lysozyme found in tears It breaks down bacteria on eyes surface Saliva Contains molecules which kill pathogens Stomach Contains hydrochloric acid which kills pathogens 3 of 7 Non-specific defences in humansMICROBIAL 3) Microbial Gut Pathogens compete with bacteria which naturally lives in the gut, in order to survive 4 of 7 Plants Physical Defences Waxy cuticle Found on leaves Waterproof barrier Reduces risk of infection form pathogens transferred in water as it prevents water form collecting on the leaf Cell walls Made from celluose Physical barrier against pathogens 5 of 7 Plants Simple Immune System Produce antimicrobial substances Phytoalexins may be produced, this disrupts the cell structure of fungi and bacteria 6 of 7 Why plants' defences against pathogens are importa Strart of food chain Ability to defend themselves helps out other organisms Example: Damage to crops can threaten human food security 7 of 7
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