| define infection | when pathogens enter a cell or tissues and bypass barriers causing symptoms |
| define immunity | the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitised white blood cells |
| define antibiotic | chemicals that kill or stop the growth of bacteria |
| define immunogenic | an antigen that causes an immune response |
| define septic | with the presence of an infectious pathogen |
| define aseptic | absence of an infectious pathogen |
| define disinfectant | a chemical used to destroy microbes in the environment |
| define antiseptic | chemicals used to destroy microbes on humans |
| define selective toxicity | chemicals which are toxic to bacteria but not human cells |
| define broad spectrum antibiotic | an antibiotic which is effective against many bacteria |
| define narrow spectrum antibiotic | an antibiotic which is effective against 1 or 2 specific bacteria |
| define sensitive | a bacteria that is killed by a standard dose of an antibiotic |
| define resistant | a bacteria that is not killed by any dose of an antibiotic |
| 4 types of immunity | natural active immunity
natural passive immunity
artificial active immunity
artificial passive immunity |
| what is natural active immunity? | arises from being exposed to an antigen |
| what is natural passive immunity? | the result of crossing of the mother's antibodies through the placenta and their presence in breast milk |
| what is artificial active immunity? | acquired through vaccinations which stimulate the immune system to the produce of antibodies |
| what is artificial passive immunity? | antibodies are injected into the body |
| define immunisation | the process of protecting people from infection with passive or active artificial immunity via vaccination |
| define vaccination | the process by which immunisation is achieved
they introduce weaker strains of the pathogen or a pathogen that has been killed |
| what is the evolutionary race? | the struggle between pathogens and their hosts to outdo each other |
| evasion mechanisms pathogens use | make their cell walls stronger
produce enzymes that break down antibiotics
actively boot out antibiotics that enter the cell |
| what are bacteriostatic antibiotics? | antibiotics which inhibit the growth of bacteria by stopping protein synthesis and production of nucleic acids so bacteria cannot divide and grow |
| what are bacteriocidal antibiotics? | they kill bacteria by destroying their cell wall causing lysis |
| investigate the effect of different antibiotics on bacteria | heat forceps over a Bunsen burner until they burn bright orange
label the petri dishes one for the mast rings and the other for water as the control
use the sterile forceps to place a mast ring in one of the petri dishes under the Bunsen burner
use the sterile forceps to dip a disk of paper into some ethanol then let it dry over the Bunsen
dip the disk in water then place the disk in the other petri dish
tape the petri disk lightly then incubate at 30°C for 24 hours
measure the zone of inhibition
carry out repeats to find the mean |
| how do hospitals prevent and control infection? | follow a strict code of practice
hands are washed with alcohol based antibacterial gel
suitable clothing is worn
all equipment is sterilised before use
no equipment is shared between patients and/or staff |
