infection and response

• communicable disease - a disease caused by a pathogens that can be passed from one person to another
• pathogen - a microorganism that causes infectious disease in a host organism
• host - the organism in which a pathogen can live
• bacteria's properties

  single celled organism

  release toxins

  binary fission
• binary fission - the process by which bacteria divide to produce two new bacteria rapidly
• virus' properties

  smaller than bacteria

  virus enters cells and takes over

  reproduce inside cells
• fungi's properties

  can be singular or multi celled

  mainly affects plants
• protists' properties

  single celled organisms

  need a vector to transfer to the host
• how are pathogens spread?

  air (droplet infection)

  contact (direct or indirect)

  water
• tears, mucus, earwax, stomach acid, skin, and scabs are all examples of what?

  non specific defences
• how does phagocytosis work?

  White blood cells engulf and digest the pathogen.
• how do antitoxins work?

  the white blood cell releases antitoxins that attach to the pathogen's toxins and neutralise it.
• how do antibodies work?

  the white blood cell creates antibodies that are specific to antigens of bacteria. the antibody is stored in a memory cell, so when reinfected, the antibody can be rapidly replicated and fight the infection much faster.
• what type of pathogens are injected when given a vaccination?

  dead, weak or inactive
• how do vaccinations work?

  a dead or weakened pathogen is injected into the blood, which the white blood cell creates antibodies to fight the antigens for. the antibodies attach to the antigens, clump together and the white blood cells engulf and destroy. when reinfected, the memory cells can replicate the antibodies rapidly and to a much larger scale.
• what is herd immunity?

  Protection against a disease that occurs when a large percentage of a population becomes immune, either through vaccination or previous infection, reducing the spread of the disease.
• what are antibiotics?

  a substance that slows or stops the growth of a bacteria.