communicable diseases - CH5

communicable disease

an infectious or contagious disease

health

state of physical and mental well being not just the absence of disease

diet, stress, environment and life situations

factors affecting health

virus

lives and reproduces inside of your cells causing cell damage

bacteria

reproduce rapidly and produce toxins which make you ill

by air, direct contact, water

how are pathogens spread?

measles

virus, red skin and rash, spread by coughing and sneezing, no treatment

hiv/ aids

virus, mild flu like symptoms whilst attacking immune cells , sexual contact or exchange of bodily fluids, no vaccine, no cure but aids can be stopped from developing by antiretroviral drugs

tobacco mosaic virus

virus, mosaic pattern on the leaves, spread by direct contact and insects as vectors, can grow resistant strains and pest control

bacteria, fever, cramps and diarrhoea, caused by eating uncooked or contaminated food, poultry are vaccinated against it

salmonella

bacteria, thick yellow discharge and pain urinating but some have no symptoms, sexual contact, treated with antibiotics

gonorrhoea

agrobacterium tumefaciens

bacteria, causes unspecialised crown galls, however helpful for scientists

fungus, causes purple or black spots on leaves, the fungus is carried by wind or in water, fungicides can help treat and prevent the spread

rose black spot

protist, fever, shivers and effects on liver and red blood cells, spread by mosquitoes, prevention includes mosquito nets

malaria

phagocytosis

a red blood cell which engulfs the pathogen and enzymes break down and destroy the pathogen

antitoxins

neutralise the pathogen’s toxins by binding to them

antibodies

attach to the antigens as they are complientar in shape and kill the pathogen

antigen

protein on the cell which lets the body recognise if they’re harmful or not

body’s defences

stomach acid, mucus in trachea, bronchi and in nose, skin as a barrier

physical defences in plants

cell wall, waxy cuticle on leaves

mechanical defences in plants

mimicry, thorns, leaves that drop

chemical defences in plants

antibacterial chemicals e.g. mint

lymphocytes

white blood cells that produce antibodies