Topic 6

Cards (41)

  • Antibiotics are drugs that destroys microorganisms or prevent them from reproducing. Work with bacteria but not viruses.
  • selective toxicity - interfering with pathogens but with minimal damage to human host cells
  • a bacteriostatic antibiotic is one that completely inhibits the growth of microorganisms. example tetracycline
  • a bactericidal antibiotic is on that destroys almost all bacteria. Example penicillin
  • Bactericidal antibiotics are used in severe and dangerous infections, or when someone’s immune system is suppressed
  • a broad spectrum antibiotic destroys a wide range of harmful and good bacteria, and other pathogens
  • a narrow spectrum antibiotic targets one or two specific bacteria
  • what does effectiveness of an antibiotic depend on?
    concetration. local ph. susceptibility of pathogen.
  • antibiotic resistance is caused by mutations. eg. change in active site of an enzyme, change to ribosomes or change to transport proteins.
  • vertical gene transfer is through binary fission, and all the genes are passed down through generations. a population can quickly become resistant. this is due to natural selection
  • horizontal gene transfer is done by conjugation. plasmids are transferred through a pilus into another cell, creating two identical cells.
  • how can hygiene be used to control spread of resistance?
    hand gels. isolation of infected patients. screening on arrival. cleaning.
  • Endotoxins are lipopolysaccharides. They are part of the cell membrane.
  • Are endotoxins gram negative o r positive or both?
    negative
  • are exotoxins gram negative, positive or both?
    both
  • Exotoxins are soluble proteins that are released from reproducing bacteria in the host cell
  • effects of exotoxins: damages cell membranes, poison, act as competitive inhibitors (which can cause internal bleeding)
  • effects of endotoxins: fever, vomit
  • what is disease is caused by endotoxins?
    salmonella
  • what disease is caused by exotoxins?
    staphylococcus
  • the humoral immune response is the action of B cells producing antibodies, it’s associated with the non-cellular part of blood
  • cell mediated immune response is the production of specialised lymphocytes called T cells
  • where are B lymphocytes found?
    bone marrow, femur
  • where are T lymphocytes matured at?
    thymus gland
  • How is stem rust fungus spread between plants?
    wind
  • cereal crops and berberis are most affected by stem rust fungus
  • symptoms of stem rust fungus:
    • weakened stem
    • water loss
    • pustles on epidermis
  • stem rust fungus infects plants with spores. they germinated on the plant, and produce hyphae which enter via the stomata. it grows into mycelium , which produces enzymes that digest plant and absorb nutrients.
  • treatment of flu:
    • antiviral medication
    • antibiotics (secondary infections)
    • painkillers (for symptoms)
  • symptoms of flu:
    • headache
    • coughing sneezing
    • muscular joint pain
    • fever
  • how is flu passed on?
    droplet infection. direct contact.
  • influenza antigen binds to receptor on host cell and injects viral dna. biochemistry taken over, cell produces new virus particles. cell lysis, so viruses released
  • active natural immunity is our immune system. Antibodies are formed, pathogens are destroyed.
  • passive natural immunity - antibodies are passed to the baby from mother during pregnancy, and from breast milk (particularly colostrum). Immunity is only temporary, as antibodies are not replaced.
  • active artificial immunity is vaccines. a small amount of antigen or dead pathogen is inserted into blood stream. immune system produces antibodies, so memory cells form, and will attack quicker if we actually get the disease.
  • passive artificial immunity - antibodies are formed in someone and extracted and given to someone else. temporary as cannot be replaced
  • eradicating - if the pathogen is completely non-existent. eg small pox. the pathogen only exists in 2 labs in the world.
  • elimination - the disease is gone but pathogen remains present in animals or soil. immunisation continues. eg polio
  • what % need to be vaccinated for herd immunity to be effective?
    80
  • pros of vaccination
    • protection of yourself
    • protection of others
    • treatment costs kept low