Disease Flashcards
outline 4 ways a pathogen is directly spread
physical contact, faecal, droplet infection, transmission via spores
state an way of indirect transmission in animals
vector via an animal
outline 4 social factors that can affect transmission of a pathogen
overcrowding, poor ventilation, poor health, migration
outline the process of indirect transmission for a plant
spores or bacteria will attach to insect then it will go to the plant
what pathogen causes tuberculosis and ring rot?
bacteria
what pathogen causes HIV/AIDS and influenza?
virus
what pathogen causes malaria, tomato late blight?
protoctista
what pathogen causes black Sigatoka, ring worm, athletes foot?
fungi
what are 7 physical plant defences ?
cellulose, lignin, waxy cuticle, bark, stomatal closure, callose, tylose
how does the cellulose cell wall act a physical and chemical barrier to pathogens?
it is a physical barrier and it releases certain chemicals when a pathogen is detected
how is lignin a physical defence?
it is waterproof to stop water bourne pathogens and is almost completely indigestable
how is the waxy cuticle a physical barrier?
prevents water collecting and entering cell surfaces so the absence of water prevents any pathogens
how is stomatal closure a physical defence?
will detect pathogens and close to stop them entering through air Bourne
what is the role of callose?
large polysaccaride deposit that blocks phloem seive tubes to stop a pathogen spreading
what is the role of tylose?
a balloon like swelling that fills and blocks xylem vessle to stop the spread of water that could contain pathogens. it also contains terpines(chemical) that are toxic to pathogens
what are 6 active defences of a plant ?
cellulose cell wall thickens with extra cellulose so becomes harder, deposition of callose, oxidative bursts, increase in production of a chemical, necrosis and canker
how does necrosis stop a pathogen?
cell suicide, by killing cells around infection it will stop the spread further around the plant, inniciated by injury apon a cell
how does Canker stop pathogen?
causes death of cambium tissue in the bark to stop the spread of pathogen
how do oxidative bursts stop pathogen ?
the burst produce highly reactive oxygen molecules that damage cells of invading pathogens
outline 5 chemical defences of a plant?
terpenoids, phenols, alkaloids, defensive proteins, hydrolytic enzymes
what are terpenoids?
essensial oils that are antibacterial and fungal
how do phenols stop pathogens?
antibacterial and fungal, tannins In the bark inhibit attack by insects which deactivates the salivary and digestive enzymes so they dies, therefore prevents transmission of pathogens
how do alkaloids stop pathogens ?
nitrogen containing compound which give a bitter taste to bark to inhibit herbivoirs from feeding on them
what are 3 hydrolytic enzymes and their function
chitinases - break down fungal cells
glucanases - hydrolyses glycosidic binds in glucans
lysosomes - degrade bacteria cell walls
what are 6 primary non specific defences in animals agains pathogens ?
skin, blood clotting, mucous membranes, inflammation, expulsive reflexes, wound repair
describe the process of blood clotting
following a break in the skin there is a cascade of events that leads to clotting. damage to blood vessel wall exposes collogen and releases clotting factors, platlets binds to collogen (release of clotting factors) which then cause the enzyme thrombokinase to activate, which( along with calcuim ions) converts prothrombin into active thrombin. Active thrombin converts soluble fibrinnogen into insoluble fibrin which attach to platlets in plug and form a mesh which traps red blood cells and platlets to form a clot.
describe the process of skin/ wound repair once a blood clot has formed
it will form a scab which shrinks as it drys drawing sides of the cut together so the skin can be repaired under the scab. collogen is deposited, stem cells divide to form new cells which migrate to edges and differenciate. new bllod vessels form to supply oxygen to new cells which contracts to draw edges in to complete the process.
describe the process of inflammation
mast cells detect if tissue is infected then release histamine which signals to other cells and causes vasodialation to let in fluid (containing WBC) into the tissue. this leads to increase in production of fluid to create swelling. This is drained into lymphatic system where it comes into contact with lymphocytes and this inniciates immune response
how is skin a primary non specific barrier to pathogens?
1st level of defence, and doesn’t target a specific pathogen. the epidermis have keratinocytes which migrate to surface then cytoplasm is replaced with keratin (keratinisation) these dead and hard cells are a barrier to pathogens
how is mucus membranes a primary non specific defence ?
will trap any pathogen on its own (without stimulation). epithelial layer will contain goblet cells which secrete mucus and extra mucus-secreting glands under. this traps pathogens, ciliated epithelium will waft mucus where it can be swallowed into stomach and killed
how do expulsive reflexes stop pathogens ?
when a pathogen is detected in an area prone to pathogens, they will cough, sneeze or vomit to expel the microorganisms out of the body