antibiotics Flashcards
What are antibiotics and give me a example
inhibit processes in bacterial cells but not in the host organisms
- inhibit the building of bacterial of bacterial cell walls preventing the bacteria from dividing causing them to die
will antibiotics destroy viruses
Antibiotics will not work against viruses, as viruses reproduce inside cells. It is difficult to develop drugs that kill viruses without also damaging the host’s tissues
how can you grow bacteria in a lab
bacteria are cultured in a growth medium containing nutrients for growth
what can a growth medium be
nutrient broth solution or agar jelly
what is used to multiply this quickly
Warmer temperatures promote faster growth, but in a school lab the maximum allowed temperature for growth is 25°C as less harmful pathogens are likley to grow at this temperature
how do you make a agar plate
hot agar jelly is poured into a plastic petri dish
what comes after pouring agar jelly
let it cool and inoculating loops are used to transfer microorganisms to agar jelly then microorganism multiply
why is Only lifting the lid of the petri dish a little is vital
to reduce the risk of contamination by other microorganisms. It is not to prevent air from entering, as oxygen is still required by bacteria grown in school labs (more harmful bacteria tend to be anaerobic).
what are aseptic techniques name 3
sterilise the petri dish and growth medium by passing through a flame with high pressure and temperature to kill microorganisms
inoculating loop must be sterilised by passing through hot flame so microorganisms are killed
lid should only be removed briefly when transferring bacteria so microbes don’t enter
petri dish should be covered with lid to prevent microorganism entering
petri dish stored upside down to prevent condensation from falling onto agar
what are aseptic techniques name 3
- inoculating loop sterilised with hot flame to kill unwanted microorganisms
- petri dish stored upside down to prevent the drops of condensation on agar
- all petri dish and growth mediums sterilised to kill microorganisms by using high pressure and temperature
- petri dish and cultures covered with lid to prevent microorganisms entering
Explain the entire procedure of the :
Investigate the effects of antiseptics, antibiotics or plant extracts on microbial cultures
1) place paper discs soaked in different antiseptics and antibiotics onto agar plate
2) discs should diffuse in agar jelly and antibiotic resistant bacteria will continue to grow however non resistant bacteria will die and clear area left on discs
3) leave the plates for 48hrs at 25 degrees
what can u analyse from the results
that the more effective the antibiotic is the larger in the inhibition zone
name a control of the experiment
a paper discs that hasn’t been soaked in antibiotic to be able to differentiate the growth of bacteria around control disc and antibiotic disc due to effect of antibiotic
ho can you calculate the inhibition zone
pie r squared
to get diameter get mean of the circle or add height and width and divide by 2
how are drugs discovered
Traditionally, drugs were extracted from plants and microorganisms
