4.1.1 disease Flashcards
(47 cards)
what are the two bacterial diseases to know
animals: tuberculosis
plants: ring rot
what are the three viral diseases to know
HIV / AIDS
tobacco mosaic virus
influenza
what are the two protista diseases to know
malaria (plasmodium) and tomato/potato late blight
what are the two fungal diseases to know?
athletes foot and black sigatoka
how can pathogens cause harm?
through directly damaging tissues or through release of toxins
outline tuberculosis
a bacterial disease which affects humans. transmitted through ariborne droplets. cause harm by damaging lung tissue and suppressing the immune system. cured using antibiotics and prevented through vaccination
outline ring rot
bacterial disease which infects potatoes, tomatoes and aubergines. it damages leaves, tubers, and fruit. transmitted through infected tubers and micropropogation of plantlets from infected plants. reduces crop yield.
what is a virus
a non-living infectious agents. smaller than bacteria and consist of genetic material (DNA or RNA) surrounded by protein. replication occurs within the host cell by taking over the host’s biochemistry to reproduce. many evolve and adapt to their host
outline HIV / AIDS
transported around the blood until it attaches to a protein on the T helper cells. HIV positive is when a person is infected. AIDS is when the replicating viruses in the helper T cells interfere with normal immune function. when T helper cells are destroyed by the virus, the host is unable to produce adequate immune responses to other pathogens so is left vulnerable. spread through direct contact of bodily fluids
outline influenza
infects the ciliated epithelial cells of the gaseous exchange surfaces. transmitted by airborne droplets.
outline TMV
infects plants, causes damage to leaves reslting in mosaic pattern, damages flowers and fruits too. damage prevents plant from growing. transmitted by direct contact or fomites
what are protista?
eukaryotes which are unicellular, or cells grouped in colonies. pathogenic protista are parasites and are usually transmitted by a vector.
outline malaria
protoctista disease caused by Plasmodium, which is spread to humans through female anopheles mosquito vectors. plasmodium reproduces sexually and asexually within the host. passed by biting mosquitos. Plasmodium infects the red blood cells, the liver, and the brain. no cure.
outline potato blight
a fungus-like protists which causes potato blight and tomato late blight. has hyphae which enter plant and damage leaves and fruit. transmitted by spores that travel on the wind or by animals and insects.
what are fungi
eukaryotes that cause many plant diseases. when they reproduce they produce millions of spores which spread huge distances
outline black sigatoka
fungal disease that infects bananas. hyphae damages the leaves making them black which prevents photosynthesis. transmitted by spores from one plant to the next through the wind. can be killed by fungicides
outline athletes foot
only infects humans, a type of ring worm that thrives in warm damp regions like between toes. causes skin to crack and to become scaly leading to itchiness and soreness. spread by direct contact or fomites. curable with antifungal cream
what are the three direct modes of transmission?
direct contact- touching, kissing, sexual contact
inoculation: animal bites, sharing needles, cuts in skin
ingestion- drinking and eating contaminated water and food
what are the three indirect modes of transmission
vectors- transfer communicable diseases from one host to another
fomites: inanimate objects
droplet inhalation- minute droplets of saliva and mucus inhaled from others.
what barrier defences do plants have?
bark, waxy cuticle, cellulose cell wall, stomatal closing
outline plant responses to infection
1) antibacterial chemicals and proteins- to trigger cell wall fortification.
2) plant produces callose- highly branched polysaacharide which is deposited between cell walls and membranes, they act as a barrier to prevent pathogen spread. lignin is added to strengthen the barrier. Callose blocks sieve plates in the phloem, sealing off the infected part.
outline non-specific animal responses to infection
skin, blood clotting, mucous membranes, lysozymes, expulsive reflexes, inflammation, fevers
outline blood clotting as a non-specific primary defence
- skin is broken
- platelets are activated
- platelets release substances
- substances activate enzyme thromboplastin
- causes production of fibrin fibres
- form a mesh over wound (clot)
- clot dries to a scab
outline inflammation as a primary non-specific defence
- mast cells release histamine
- leads to redness and swelling
- histamine makes capillaries more permeable so more tissue fluid is made
- mast cells release cytolines to attract white blood cells (chemotaxis)
- macrophages detect and engulf pathogen
