infection and response

• types of pathogen: bacteria, viruses, fungi, protists
• pathogens are microorganisms that enter the body and cause disease
• bacteria are very small cells
• bacteria make you feel ill by producing toxins that damage your cells and tissues
• viruses are not cells, they are even smaller then a bacteria cell
• viruses live inside cells and replicate themselves using the cells machinery to produce copies of themselves. the cell will then burst, relesing all the viruses
• protists are single celled eukaryotes
• there are different types of protists, some are parasites
• parasites live on or in other organisms and can cause damage, they are often transferred by a vector
• some fungi have a body which is made up of hyphae these can grow and penetrate human skin and the surace of plants
• pathogens can be spread by:

  water

  air

  direct contact
• measles is a viral disease
• measles is spread by droplets from an infected persons sneeze
• people with measles develop a skin rash and a fever
• HIV is a virus spread by sexual contact or by exchanging bodily fluids
• TMV is a virus that effect plants eg. tomatoes
• TMV leaves a mosaic pattern on leaves and stunts growth because it limits photosynthesis
• rose black spot is a fungus that causes purple spots on leaves of rose plants, the leaves can turn yellow and drop off
• malaria is caused by a protist
• malaria causes repeating episodes of fever can be fatal
• salmonella is a type of bacteria that causes food poisoning
• salmonella can cause fever, vomiting, diarrhoea, stomach cramps
• the symptoms of salmonella are caused by toxins produced by the bacteria
• gonnorea is a bacteria that causes a sexually transmitted disease
• symptoms of gonorrhoea: pain when you urinate, thick yellow or green discharge from vagina or Penis
• the spread of disease can be prevented by

  being hygienic

  destroying vectors

  isolating infected inderviduals

  vaccination
• the skin acts as a barrier to pathogens. it also secretes antimicrobial substances which kill pathogens
• hairs in your nose trap particles that could contain pathogens
• trachea and bronchi secrete mucus to trap pathogens
• the stomach contains hydrochloric acid this kill pathogns
• white blood cells can engulf bacteria and viruses and destroy them
• vaccinations involve injecting small amounts of dead or inactive pathogens into the body. these carry antigens witch cause your bodies to produce antibodies to attack them.
• pro of vaccination: vaccines have helps control a lot of diseases that were one common
• con of vaccines: you could have a bad reaction, somtines they dont work
• painkillers relive pain but don't actually cure it
• antibiotics kill the bacteria without killing your cells
• penicillin is an antibiotic
• bacteria can mutate to become resistant to an antibiotic
• to slow down the rate of resistant strains, doctors don't overprescribe antibiotics. also finish the whole course of antibiotics
• many drugs originally came form plants