preventing and treating diseases

• what is natural active immunity?

  • immunity which occurs from the response of the body to the invasion of a pathogen
  • during the secondary immune response, the body recognises and immediately destroys pathogen from memory cells, so said to be immune, and active as the own body is producing antibodies and memory cells
• what is natural passive immunity?

  Immunity acquired through the transfer of antibodies from another source, such as a mother to her baby through the placenta/colostrum
• why and where does a baby receive natural passive immunity from their mother?

  • receives from placenta/colostrum high in antibodies (milk from mother at birth)
  • has a weak immune system
  • failure to make antibodies
  • so baby has some immunity to disease at birth
  • same level of antibody protection disease as the mother, related to the pathogens found in her immediate environment
  • lasts until baby makes own antibodies
• what is artificial passive immunity?

  where antibodies are formed in one individual, extracted and injected into the bloodstream of another
• state 2 examples of cases which can be treated using artificial passive immunity

  • rabies
  • tetanus
• what is artificial active immunity?

  body stimulated to make antibodies to combat a safe dead or inactivated form of antigen/pathogen eg vaccine
• what is herd immunity?How does it prevent epidemics?

  • Protection against a disease that occurs when a percentage of a population is vaccinated, and those who are not vaccinated and immune gain protection from those around them that have immunity from being vaccinated
  • mass vaccination can prevent the spread of a pathogen into the wider population
  • provides long term immunity
• why are vaccines changed regularly?

  to remain effective, as pathogens can mutate, antigens can change and the immune system may not recognise them
• state an example of a vaccination programme that takes place globally

  flu
• state three examples of medicinal drugs

  • penicillin - extracted from mould, antibiotic- used to treat bacterial diseases
  • aspirin- from willow bark - painkiller, and for anti inflammatory drugs
  • digoxin- from foxgloves, heart drug to treat atrial fibrillation and heart failure
• why is it important to maintain biodiversity for medicine?

  prevents the likelihood of destroying a plant or organism that could be used as medicine to combat a particular disease which may not have been discovered yet
• what is personalised medicine?

  combination of drugs that work with an individual's combination of genetics and disease
• what is meant by pharmacogenomics and why does it have potential?

  • involves analysis of the human genome
  • interweaving knowledge of drug actions with personal genetic material
  • can be used to treat breast cancer which is caused by a gene
• what is synthetic biology and why does it have potential?

  • through genetic engineering, populations of bacteria can be developed to produce drugs that would otherwise be too rare, expensive/unavailable
  • mammals can also be GM to produce therapeutic proteins in their milk, great potential for medicine
  • nanotechnology- small particles can be used to deliver drugs very specific to sites within a pathogen
• what is selective toxicity?

  when antigens interfere with metabolism of bacteria without affecting the metabolism of human cells
• what medicine became widely used in the 20th century and why?

  • antibiotics
  • for the first time, doctors found effective treatments against communicable diseases
  • reduced the number of deaths from communicable diseases
• why are antibiotics not as useful now as they were before and how has this happened?

  • bacteria develop antibiotic resistance
  • random mutation during bacterial reproduction causes bacteria to be resistant to an antibiotic, it will survive and reproduce and this resistance is passed onto offspring
  • bacteria are now resistant to almost all our antibiotics
• why is antibiotic resistance now a concern?

  • over-subscription of antibiotics can over-expose bacteria to these conditions and accelerate natural selection of antibiotic strains
  • prime cause of rise in antibiotic resistance
• state 2 examples of antibiotic resistant bacteria

  MRSA and C. difficile
• how can antibiotic resistance be reduced?

  • prevention of over-subscription- to prevent resistant strain surviving
  • complete full round of medication- to prevent resistant strain surviving
  • good hygiene in hospitals care homes and in general- reduces the spread of infections and antibiotic resistant strains
• how is the problem of antibiotic bacteria being solved?

  • development of new antibiotics using computer modelling
  • looking at sources of antibiotics in a wide variety of places
  • announced that anyone who could come up with effective cure for antibiotic resistant bacteria would be rewarded a grand prize- encourages new medicines to be developed