Zusammenfassung der Ressource
4.1.1 Communicable diseases, disease prevention and
immune system
- (a) the different types of pathogen that can cause communicable
diseases in plants and animals
- •bacteria – tuberculosis (TB), bacterial meningitis, ring rot (potatoes, tomatoes)
- •virus – HIV/AIDS (human), influenza (animals), Tobacco Mosaic Virus (plants)
- •protoctista – malaria, potato/tomato late blight
- fungi – black sigatoka (bananas), ring worm (cattle),
athlete’s foot (humans)
- (d) the primary non-specific defences against pathogens in animals
- skin, mucous membrane, blood clotting, inflammation,, wound repair, empulsive reflexes
- (e) (i) the structure and mode of action of phagocytes (ii) examination and drawing of cells observed
in blood smears
- (f) the structure, different roles and modes of action of B and T lymphocytes in the specific immune
response
- T helper cells
- T killer cells
- T regulatory cells
- B plasma cells
- memory cells
- (b) the means of transmission of animal and plant communicable pathogens
- Direct transmission
- droplet infection
- coughing and sneezing
- sexual intercourse
- e.g HIV
- touching an infected organism
- e.g Athlete's foot
- Indirect transmission
- air
- water
- food
- vector
- e.g malaria- mosquitoes are vectors that spread plasmodium
- (c) plant defences against pathogens
- waxy cuticle provides a physical barrier
- plant cells are surrounded by cell walls
- produce a polysaccharide called callose which makes it harder for pathogens to enter
cells. At the plasmodesmata it limits the spread of viiruses between cells
- (g) the primary and secondary immune responses