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describe how viruses make people ill
very small
move into cells and use the biochemistry of it to make many copies of itself
this leads to the cell bursting and releasing all of the copies into the blood stream
the damage and destruction of the cell makes the individual feel ill
describe how bacteria make people ill
small
multiply very quickly through dividing by a process called binary fission
produce toxins that can damage cells
describe how protists make people ill
some and parasitic meaning they use humans and animals as their hosts ( live on and inside causing damage)
describe how fungi makes people ill
produce spores which can be spread to other organisms
what is a fungus
can be either single-called or have a body made of hyphae (threadlike structures)
3 ways disease can be spread
direct contact
by water
by air
how can direct contact spread disease + examples
touching contaminated surfaces eg kissing, contact with bodily fluids, microorganisms left from faeces
how can water spread disease
drinking or coming into contact with dirty water
how can air spread disease + examples
pathogens can be carried in the air and then breathed in for example droplet infection where when sneezing, coughing, talking expels pathogens in droplets which can be breathed in
how to limit the spread of disease (pathogens)
improve hygiene
reduce contact with infected people
remove vectors
vaccination
name 3 viral diseases
tobacco mosaic virus
HIV
Measles
symptoms of measles
fever and red skin rash, can lead to other problems like pneumonia (lung infection), encephalitis (brain infection) and blindness
how is measles spread
droplet infection
how is measles prevented
vaccinations for young children to reduce transmission
symptoms of HIV
initially flu-like symptoms, then virus attacks the immune system and leads to AIDS
how is HIV spread
by sexual contact or exchange of bodily fluids such as blood
how is HIV prevented
the spread - using confond, not sharing a needles, screening blood when ins used in transfusions, mothers with HIV bottle-feeding their children
the development into AIDS - use of antiretroviral drugs to stop the virus replicating in the body
what plant goes tobacco mosaic virus commonly affect
tomato plant
symptoms of tobacco mosaic virus
discolouration of the leaves, affected part of leaf cant photosynthesise resulting in a reduction of the yield
how is tobacco mosaic virus spread
contact between diseased plants and healthy plants insects act as vectors
how to prevent tobacco mosaic virus
good field hygiene, pest control, growing TMV- resistant strains
why are bacterial diseases on the rise
becoming resistant to antibiotics
what is salmonella food poisoning
bacteria that live in the gut of different animal which we ingest when we eat meat
symptoms of salmonella
stomach cramps
vomiting
diarrhoea
fever
all caused by the toxins they secrete
how is salmonella spread
bacteria found in raw meat and eggs, unhygienic conditions
preventing salmonella
poultry are vaccinated against salmonella, keeping raw meat away from cooked food, wash hands and surfaces when handling it, cook food thoroughly
symptoms of gonorrhoea
thick yellow or green discharge from the vagina or penis, pain when urinating
how is gonorrhoea spread
STD spread through unprotected sexual contact
prevention of gonorrhoea
by using contraception such as condoms and antibiotics (used to be treated with penicillin but many restraint strains are developing)
name a fungal disease
rose black spot
symptoms of rose black spot
purple or black spots on leaves of rose plants, reduces the area ir the leaf available for photosynthesis leaves turn yellow and drop early
how is rose black spot spread
the spores of the fungus are spread in water or by wind
how is rose black spot prevented
by using fungicides or stripping plant of affected leaves and burning them
name a protist disease
malaria
what is malaria
caused by protists pathogens that enter red blood cells and damage them
symptoms of malaria
fevers and shaking (when the protists bursts out of blood cells)
how is malaria spread
the vector is the female anopheles mosquito in which the protists reproduce sexually. When the mosquito punctures the skin to feed on blood the protists enter the human bloodstream via their saliva
what does the non-specific defence system do
prevents pathogens from entering the body
4 elements of non-specific defence system
skin
nose
trachea + bronchi
stomach
how does the skin benefit the non-specific defence system
physical barrier
produces anti microbial secretions to kill pathogens
good microorganisms known as skin flora compete with bad ones for space and nutrients
how does the nose benefit the non-specific defence system
has hairs and mucus which prevent particles from entering your lungs
how does the trachea and bronchi benefit the non-specific defence system
secrete mucus in order to trap pathogens
cilia (hair like structures of cells) beat to waft mucus upwards to be swallowed
how does the stomach benefit the non-specific defence system
produces hydrochloride acid that kills any pathogens in your mucus, food , drink
what’s the role of the specific immune system
acts to destroy any pathogens whoch pass through the non-specific immune system to the body
what 3 different ways can white blood cells act
phagocytosis
producing antibodies
producing antitoxins
how does the step of phagocytosis in the specific immune system help to protect you?
engulfing and consuming pathogens
this destroys them meaning they can no longer make you feel ill
how does the step of producibg antibodies in the specific immune system help to protect you?
each pathogen has an antigen on their surface which is a structure which a specific complementary antibody can bind to, once the antibodies bind to the pathogen the pathogens start to clump together making it easier for them to be found by white blood cells
what happens when you become infected again with the same pathogen?
the specific complementary antibodies will be produced at a faster rate - the individual will not feel the symptoms of the illness they are said to be immune
how does the step of producing antitoxins in the specific immune system help to protect you?
they neutralise the toxins released by the pathogen by binding to them
what do vaccines do
making an individual immune to a certain disease they’re protected against it before they’re been affected
what is herd immunity
immunising a large proportion of the population, limits the spread as there are less people to catch the disease from
how do vaccines work
they contain a dead or inactivated form of the pathogen
this stimulates white blood cells to produce antibodies complementary to the antigens on the pathogen
this replicates the first infection of a disease just with no symptoms
2 advantages of vaccines
eradicated many diseases (smallpox) and reduced the occurrence of many (rubella)
epidemics can be prevented through herd immunity
2 disadvantages of a vaccine
not always effective in providing immunity
bad reactions (fevers) can occur in response to vaccines
what are antibiotics
medicines that kill bacterial pathogens inside the body, without damaging body cells, they cannot kill viruses as they use body cells to reproduce, meaning any drugs that target them would affect body tissue too
what do painkillers do
treat symptoms don’t stop the disease
how can antibiotics be taken
pills
syrup
directly into blood stream
example of an antibiotic
penicillin
explain how bacteria becomes resistant to an antibiotic
mutations can occur during reproduction resulting in certain bacteria bon longer being killed by antibiotics
when bacteria is exposed to antibiotics only the non-resistant ones die
the resistant bacteria survive and reproduce meaning the population of resistant bacteria increases
how to prevent the development of resistant strains
stop overusing antibiotics
finishing courses of antibiotics to kill all of the bacteria
how are drugs tested
preclinical testing and clinical trials
how are the chemicals that plants use to kill pests and pathogens helpful with an example
can treat symptoms of human diseases
aspirin is used as a painkiller and it originates from willow
how was penicillin made
Fleming was growing bacteria on plates he found moult in his culture plates, with clear rings around the mould indicate oh there was no longer any bacteria there, he found the mould was producing a substance called penicillin which killer bacteria
what is clinical testing
uses volunteers and patients
how does clinical testing work
first tested in healthy volunteers with low dose to ensure no harmful side effects
tested on patients to find most effective dose
half the patients get a placebo half get the actual one to observe the effect of the drug
can be single/double blind
then are peer reviewed
