Studied by 17 people
What are the 4 types of pathogen?
bacteria, virus, protist, fungi
What are bacteria?
very small cells 100x smaller than body cells that rapidly reproduce
How does bacteria make you feel ill?
produce toxins that damage cells and tissues
Eg: bacterial infections
salmonella, gonorrhea
How is salmonella spread?
contaminated food
What are the symptoms of salmonella?
fever
vomiting
diarrhoea
How is the spread of salmonella prevented?
food hygiene standards
vaccination of poultry
How is gonorrhea spread?
sexual contact
What are the symptoms of gonorrhea?
pain when urinating
thick yellow/green discharge from penis/vagina
How is gonorrhea treated?
antibiotics (e.g penicillin)
What is the problem with antibiotics?
some strains mutate and become resistant (e.g MRSA)
How is antibiotic resistance prevented?
not over subscribing antibiotics
How is gonorrhea prevented?
barrier methods of contraception
What is a virus?
a tiny infectious agent that use cells to replicate themselves
How does a virus make you feel ill?
cells containing reproducing viruses eventually burst, cell damage make you feel ill
Eg: viruses
measles, HIV, TMV
How is measles spread?
airborne droplets
What are the symptoms of measles?
red rash, fever
What are possible complications of measles?
pneumonia, encephalitis
How is measles prevented?
vaccination of children
How is HIV spread?
sexual contact
What are symptoms of HIV?
flu-like symptoms
How is HIV treated?
antiretroviral drugs
How does HIV make you feel ill?
attacks immune cells
What happens if HIV remains untreated?
AIDS
more susceptible to other disease
What is TMV?
Tobacco Mosaic Virus
What are the symptoms of TMV?
discoloured patches on leaves in mosaic pattern
How does TMV damage a plant?
decreases rate of photosynthesis → less growth
What is a protist?
all eukaryote, most single celled, some parasites
How do protists make you feel ill?
often carried by a vector and then live on/in other organisms causing damage
Def: vector
an organism that carries a protist without getting the disease itself
Eg: protist
Malaria
How is malaria spread?
part of malarial protists’ life cycle is inside a mosquito
mosquito pick them up and become vectors when feeding on an infected animal
mosquito spread the protist when feeding on other animals
What are the symptoms for malaria?
repeating fever
How is malaria prevented?
preventing mosquitos’ reproduction
insecticides
nets
What is fungi?
some single celled, some made up of hyphae
Def: hyphae
thread like structures
How does fungi make you feel ill?
spread by spores, penetrate human skin/plant surfaces causing disease
Eg: Fungal disease
rose black spot
What are the symptoms of rose black spot?
black/purple spots
How is rose black spot spread?
spore carried by water or wind
How does rose black spot damage rose plants?
decreases rate of photosynthesis → less growth
How is rose black spot treated?
removal of infected leaves
fungicides
How can pathogens be spread?
contaminated water
airborne droplets
direct contact
How does the body prevent pathogens entering the body?
skin
tears
mucus
hair
stomach acid = HCl
How do white blood cells attack pathogens?
phagocytosis
producing antibodies
producing antitoxins
How does vaccination work?
dead/inactive pathogens injected carrying antigens that cause body to produce antibodies to attack them
when body encounters the same active pathogens, antibodies produced much quicker
What are the pros of vaccination?
control lots of communicable diseases → prevents epidemics
What are the cons of vaccination?
don’t always work
side effects
What drugs have come from plants?
aspirin - willow
digitalis - foxglove
How was penicillin discovered?
Alexander Fleming discovered area around mould on petri dishes did not grow bacteria due to production of a substance - penicillin
What are the 3 stages of drug testing?
cells/tissues
live animals
clinical trials
Def: double blind trial
neither patient nor doctor know whether they are given the placebo
Def: monoclonal antibodies
copies of antibodies that target a specific antigen
How are monoclonal antibodies cloned on a larger scale?
fused with a tumour cell to divide rapidly
Why are monoclonal antibodies useful?
bind to a specific molecule
How are monoclonal antibodies used?
pregnancy tests
treat disease
to find specific substances
How does a pregnancy test work?
urine containing HCG binds to pigment molecules that then bind with the results line to form positive line, if HCG not present, no line forms
How are monoclonal antibodies used to treat disease?
monoclonal antibodies can help deliver drugs to a specific part of the body e.g cancer cells by recognising its antigens
How can monoclonal antibodies help identify certain substances?
can bind with a dye to indicate presence of a substance
What is the problem with the use of monoclonal antibodies?
side effects e.g fever, low blood pressure
What physical defences do plants have?
waxy cuticle
cell walls
outer layer of dead cells
What chemical defences do plants have?
antibacterial chemicals (e.g mint)
produce toxins (e.g deadly nightshade)
What mechanical defences do plants have?
thorns
hairs
droop/curl when insect lands
mimic other organisms
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