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
abacteriostatic 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?