B2

Cards (78)

  • a communicable disease is a disease that can be spread from person to person
  • what is the role of the immune system?
    to detect and destroy pathogens
  • if your immune system is weakened, which type of diseases do you become more susceptible to?
    communicable diseases
  • what is a pathogen?
    a micro-organism which can cause disease.
  • four ways pathogens can be spread
    through the air
    by direct contact
    contaminated water
    contaminated food
  • what diseases can you get through the air?
    influenza
    measles
    cold
  • what diseases can you get from contaminated water?
    cholera
  • what diseases can you get from contaminated food?
    salmonella
  • what diseases can you get from direct contact?
    athletes foot
  • how can we reduce the spread of infectious diseases?
    vaccination
    improving hygiene
    killing vectors that carry pathogens
    isolation
  • how viruses spread and multiply
    Viruses pass between humans via the air, contaminated food or water, or by direct contact. As they can't reproduce themselves, viruses have to enter one of our cells, and then use it to create multiple copies of the virus itself. Once there are a lot of copies, the viruses cause the cell to burst, and then go on to infect the neighbouring cells.
  • how can HIV be spread?
    sexual contact
    exchange of bodily fluids
  • what is AIDS
    where the immune system is so weak the person can catch unusual infections
  • what is the main symptom of TMV
    patches of leaves get discoloured
  • what are the consequences of TMV photosynthesising less?
    the plant won't be able to grow as well
    the plant won't be able to produce as many sugars
  • Bacteria release small proteins called toxins. These can damage our cells and are responsible for many symptoms of bacterial diseases
  • bacterial diseases
    salmonella
    gonorrhoea
  • ash dieback
    pathogen - fungus
    transmission - airborne spores often through the wind
    symptoms - wilting, dieback of leaves, wounds on the bark
    treatment - none
    prevention - removing infected trees, biodiversity in tree populations, restricting movement of ash trees
  • eukaryotic organisms
    animals
    fungi
    plants
    protoctists
  • Rose black spot is a fungal disease that causes purple or black spots on the leaves, which often turn yellow and fall off. This reduces photosynthesis and therefore the growth of the plant. It can be spread by water or the wind. Treatment involved spraying the plant with fungicide or destroying the affected leaves.
  • Protists are considered parasites. This means they live in a host organism and get their food at the expense of the host.
  • how can we reduce the spread of malaria
    mosquito repellent
    mosquito nets
    destroy mosquito breeding sites
  • three main causes of plant disease
    infection by micro-organisms
    attack by insects
    lack of essential minerals
  • how does the pathogen that causes crown gall disease enter the plant?
    through wounds on the plant
  • why do plants require nitrates?
    to make proteins
  • what is a symptom of nitrate deficiency (lack of nitrates) in a plant?
    stunted growth
  • why do plants require magnesium?
    to make chlorophyll
  • what is the main symptom of magnesium deficiency (lack of magnesium) for a plant?
    chlorosis - yellow leaves
  • three physical changes that indicate a plant has a disease
    stunted growth
    spots of leaves
    discolouration
  • three ways a plant disease can be identified
    compare symptoms to a gardening manual
    use testing kits that contain monoclonal antibodies
    test the DNA of the pathogens
  • what's a physical defence
    defences that physically prevent the entry of pathogens
  • what are physical defences of plants?
    strong cellulose cell walls
    waxy cuticle on stems and leaves
    layers of dead cells around the trunk
  • whats a chemical defence
    chemicals that plants secrete to destroy pathogens
  • what are chemical defences of plants?
    production of antimicrobial substances
    production of poison that kills insects
  • whats a mechanical defence
    structures that reduce the chance of being attacked
  • what are mechanical defences of plants
    hairs and thorns
    leaves that droop or curl when insects land on them
    mimicking other organisms to trick animals
  • An antigen is any substance that your body sees as foreign, which then causes your immune system to produce antibodies against it. For example, the toxins and cell walls of pathogens would be considered antigens.
  • An antibody is a protein produced by our white blood cells that binds to specific antigens. This acts as a signal to our immune system to destroy the antigen or the pathogen it is a part of.
  • The first time you're infected with a new pathogen, you normally get quite ill as it takes your body time to identify and destroy the pathogens. 
    However, in the process, you also develop memory cells, which are a special type of white blood cells that remember the pathogen for next time. 
    This means that if you're infected again your immune system can respond more quickly and powerfully - and so you don't get as ill
  • barriers that reduce the entry of pathogens
    enzymes in tears
    skin
    nose hair