Health and Disease

• Bacteri make us ill by invading our host cells and releasing toxins
• Antibiotics: Substances that slow down or stop bacteria from growing
• MMR vaccine protects people from:

  • Measles
  • Mumps
  • Rubella
• Lymphocyte: White blood cell that produces antibodies to neutralize pathogens
• Phagocyte: White blood cell that moves towards pathogens and engulfs them by using enzymes

  ORR

  They release antitoxins whcih neutralize toxins released by pathogens
• What type of drugs can be used to treat HIV:

  • Antiretrovial drugs.
• Viruses are non living (acellual) particles that can repoduce rapidly within the body.
• How viruses make us ill:

  1. For viruses to survive, they will need to replicate so they will invade our host cells.
  2. The virus paticle then inserts it's own DNA into the host cells DNA, which is then copied and used to make more viruses.
  3. Once new virus particles have been made, they cause the cell to burst, releasing new viruses to invade more cells.
  4. The damged cells is what makes us ill.
• Diseases spread by bacteria:

  • Salmonella.
  • Gonorrhoea.
• Protists:

  • Can be parasites.
  • Usually transfered by vectors.
  • Unicellular.
  • Eukaryotic.
• How to stop malaria from spreading:

  • Preventing mosquitos from breeding.
  • Put mosquito nets around your bed while your sleeping.
• Non specific defences:

  • Stomach acid.
  • Tears.
  • Mucus.
  • Skin.
• Stages of vaccination:

  1. Vaccines inject a dead or weakend form of the virus into the blood.
  2. White blood cells recognise that the antigens are foreign and produce antibodies against them.
  3. Some of these white blood cells remain as memory cells.
  4. If the pathogen enters the body again, the memory cells are able to produce antibodies faster and produce more meaning the antibody concentration will remain in the blood for longer.
  5. Next time the same pathogen infects the vaccinated person, it will be destroyed by the immune system before it can cause illness.
• How does antibiotic resistance occur:

  1. Within population of bacteria, some will have random mutation.
  2. The mutated bacteria are immune to antibiotics so they are able to survive whilst non-immune bacteria die.
  3. The resistant bacteria can reproduce rapidly because there is no competition (competition destroyed by antibiotics).
  4. When resistant bacteria reproduce, they produce genetically identical copies; they will be resistant to the antibiotcs.
• Factors to consider when testing a drug:

  • Dose - how much of the drug is needed.
  • Toxicity - is the drug safe (not to toxic).
  • Efficacy - does the drug work.
• Fungi:

  1. Fungi are unicellualr or multicellular that each have bodies made up of hyphae.
  2. The hyphae are able to grow and penetrate tisues (such as human skins and surfaces of plants).
  3. The hypahe produce spores that can spread to other plants and animals.
• How is skin a defence:

  • Covers body which prevents pathogens from coming in.
  • They secrete oils and antimicrobial substances that kill pathogens.