diseases (communicable)

• what is a pathogen?

  a microorganism that enters the body and causes diseases
• state the 4 types of pathogens?

  Bacteria, viruses, fungi, protists
• what is bacteria (1/100th the size of our body cells) ?


  very small cells that reproduce rapidly inside your body

  • they can make you feel ill as they produce toxins that damage our cells and tissues
• what are viruses (1/100th the size of our body cells)?

  not cells but they still reproduce rapidly inside our bodies

  • they live inside our cells
  • they replicate themselves using cell machinery to make copies
  • cell eventually Burst which releases all new viruses
  • the cell bursting makes us ill
• what are protists?

  eukaryotes (most single-celled)+

  • some are parasites which live on or inside another organism and cause damage
  • they are transferred by a vector
• what is fungi?

  mostly a single-celled

  • some are made from hyphae that penetrate skin and the surface of plants which causes disease
  • hyphae produce spores that spread to other plants/animals
• what are the 3 ways pathogens can be spread?

  direct contact, (contaminated)water or air
• name 3 viral diseases?

  Measles, HIV and Tobacco Mosaic virus
• How is measales spread?

  droplets from an infected person's sneeze or cough

  most people are vaccinated against it from young
• what are the symptoms of measles?

  • red skin rash
  • fever
  • can lead to pneumonia
  • may lead to brain inflammation(encephalitis)
• How is HIV spread?

  spread by sexual contact or by exchanging bodily fluids (sharing needles)
• what are the symptoms of HIV?

  1. flue-like symptoms
  2. symptoms are usually not felt for several years which is when antiviral drugs must be used
  3. it attacks immune cells
  4. may lead to other infections, cancers or AIDS
• what is tobacco mosaic virus?

  1. causes a mosaic pattern on the leaves of plants as they become discoloured
  2. therefore they cannot photosynthesis as the loose chloroplast to absorb light energy
• state a fungal disease?

  rose black spot
• what is rose black spot?

  a disease that causes purple or black spots to develop on rose plant leaves. they then turn yellow and drop off
• why is rose black spot bad for plants?

  less photosynthesis will happen leading to a lack of growth
• how is rose black spot spread and treated?

  spread: by water and wind

  treated: by using fungicides/ stripping off and destroying affected leaves
• what is malaria caused by?

  a protist that is inside a mosquito (a vector)

  • they pick it up from feasting on infected animals
  • they also give malaria to animals they feast on (into bloodstream)
• what are symptoms of malaria?

  fever
• how to prevent mosquitoes giving us malaria?

  insecticides or mosquito nets
• what are two examples of a bacterial disease?

  • gonorrhoea
  • salmonella
• what is salmonella and what are its symptoms?


  a bacteria that causes food poisoning as it releases toxins

  • fever
  • stomach cramps
  • vomiting
  • diarrhoea
• How do you get salmonella?

  by eating contaminated food
• what is gonorrhoea and what are its symptoms?

  it is a sexually transmitted disease which causes:

  • pain when urinating
  • yellow or green discharge from the vagina or penis
• How is gonorrhoea treated/ prevented?

  • penicillin but strains of the bacteria have become resistant to it
  • antibiotics
  • barrier methods
• How do you prevent the spread of disease?

  • being hygienic
  • destroying vectors
  • isolating infected individuals
  • vaccinations