Communicable diseases Flashcards
(46 cards)
What diseases does bacteria cause in plants and animals?
Ring rot, TB
What diseases does viruses cause in animals and plants?
HIV/AIDS, Influenza, Tobacco mosaic virus
What diseases does protoctista cause in animals and plants?
Malaria, Potato/tomato late blight
What diseases does fungi cause in animals and plants?
Athletes foot, Black stigatoka
What causes malaria?
Female mosquito acts a vector for protoctista, transfers saliva to other organism during feeding.
Parasite reproduces asexually in RBC in liver causing cell lysis
What is a vector?
an organism which carries a pathogen between hosts
How is pathogens spread between animals? Direct
- Direct physical contact
- Faecal/oral transmission
- Droplet infection
- Transmission by spores
What are social factors affecting the transmission in animals?
- Overcrowding
- Poor ventilation
- Poor health / diet
How is pathogens spread between animals indirectly?
Via a vector
How is pathogens spread between plants directly?
Fungi producing spores for asexual/sexual reproduction and can be carried by the wind
How is pathogens passed between plants indirectly?
Insect carrying spores attack plants
replanting infected trees
In what type of climate do fungi and bacteria reproduce rapidly in?
Warm and moist
How does the cellulose cell wall act as a physical defence?
physical barrier and has chemicals that can be activated when a pathogen is detected
How does lignin thickening cell walls act as a physical defence?
waterproof and completely indigestible
How does the waxy cuticles act as a physical defence?
prevents water collecting on cell surface since pathogens need water to survive, absence of water = passive defence
How does bark act as a physical defence?
contains chemicals
How does stomatal closure act as a physical defence?
when pathogenic cells are detected, the guard cells closen the stomata
How does callose act as a physical defence?
blocks flow in sieve tube so prevents pathogen from spreading around the plant.
How does tylose formation act as a physical defence?
a balloon-like swelling that fills the xylem vessel and plugs it producing chemicals
What are some types of active defences?
Cell walls become thickened with additional cellulose
Callose deposition
Oxidative bursts that produce highly reactive O2 molecules that damage invading organisms
increase production of chemicals
What are some chemical defences?
Terpenoids,phenols,alkaloids and hydrolytic enzymes
Have anti pathogenic properties
Define necrosis and canker
necrosis is deliberate cell suicide
canker is sunken necrotic leision in stem and branch that cause death of the cambium tissue in bark.
What are some primary defenses
skin
blood clotting
expulsive reflexes
mucuous membranes
inflammation
Describe the method of blood clotting
platelets release substances that , via a cascade of events, release fibrin which forms a network trapping the platelets and forming a clot.
