microbiology practical

Question 1

what is agar jelly used for

Answer 1

culture medium to grow bacteria

Question 2

requirements to grow bacteria

Answer 2

sterile pippette
below 25° to prevent harmful pathogens

Question 3

how can yiu avoid contamination

Answer 3

• heat culture medium and inoculating loop to kill unwanted microorganisms
• tape petri dish lid on
• store upside down to stop condensation from affecting agar

Question 4

how do you investigate the effect of antibiotics on bacterial growth

Answer 4

SPULC
• soak paper discs in diff types or concentrations of antibiotics
• place in agar plate that has bacteria covering
• use a “control” (disc soaked in sterile water) to ensure bacterial growth is due to antibiotics effect
• leave for 48 hours at 25°
• compare sizes of inhibitions zones

Question 5

why do inhibition zones form

Answer 5

• antibiotic soaks into the jelly
• antibiotic resistant bacteria can continue growing around discs
• non resistants will die
• clear area where bacteria has died = inhibition zone