Defence against pathogens

Question 1

primary defence

Answer 1

non specific

prevents pathogen from entering

Question 2

skin

Answer 2

• physical barrier
• chemical barrier
  
  • produce chemical that are microbial and lower pH, inhibiting growth

Question 3

mucous membrane

Answer 3

• protect exposes body openings
• secrete mucous, traps pathogens and contain anti-microbial enzymes

Question 4

blood clotting

Answer 4

• blood clot is a mesh of protein fibres
• plug wound
• prevent pathogen entry and blood loss
• formed in series of chemical reaction that take place whem platelets are exposes to damaged blood vessels

Question 5

inflammation

Answer 5

• sings
  
  • swelling
  • pain
  • heat
  • redness
• triggered by tissue damage
  
  • damaged tissue releases molc that increase permeability of blood vesssels
  • leak fluid into surroudnign area
  • causes swelling
• helps isolate any pathogens that may have entered damaged tissue
• molc also cause vasodilation
  
  • increases blood flow
  • bring WBC
  • makes area hot

Question 6

wound repair

Answer 6

• skin able to repairs iself and re-form a barrier
• outer layer of skin cells dividing and migrating to the edges of the wound
• the tissue below the wound contract to bring the edges of the wound clossing
• repaired using collaged fibres

Question 7

expuslive reflexes

Answer 7

• coughing and sneezing
• sneeze
  
  • mucous membranes in nostrils irritated by dust or dirt
• cough
  
  • irritation in the repiratory tract
• expel forgeign bodie

Question 8

waxy cuticle

Answer 8

• provides phusical barrier
• stop water collecting on leaf, which could reduce risk of infection of pathogens trnasferred between plants in water

Question 9

cell walll

Answer 9

phuscial barrier if pathogen makke it past cuticall

Question 10

callose

Answer 10

• polysaccharide
• deposited between plant cell walls and plasma membranes during time of stress, e.g. pathogen invasion
• makes it harder for pathogen to enter celss
• callose in plasmodesmata limits the spread

Question 11

plant chemical

Answer 11

• antimicrobial chemical
  
  • kill pathogens or prevent growth
• toxic to insects
  
  • reduces the amount of insect feeding insects and reduce the risk of infection of plant viruses by insect vectors