Required practical Investigating Microbial Growth

Question 1

Aseptic techniques include
Washing hands thoroughly

No……………… in the lab

Disinfecting work surfaces with disinfectant or alcohol

Not allowing the growth of microorganisms at ……….

Using ………… when transferring cultures

Wearing ………….

flamimg………. to prevent contamination

……….. of all used equipment

Washing …….. thoroughly

Having a lit ……… in the room

Only removing petri dish ………when necessary

Answer 1

food or drink

body temperature

flamed loops or sterile swabs

gloves and goggles

culture bottlenecks

sterilising and disposing f all used equipment

hands

Bunsen burner

lids

Question 2

When investigating the effect of antimicrobial substances on microbial growth it is essential that aseptic techniques are used
Aseptic techniques ensure

Answer 2

the microbes being investigated don’t escape or become contaminated with another unwanted, and possibly pathogenic, microbe

Question 3

Testing for bacterial antibiotic resistance using the disc diffusion method
The disc diffusion method is commonly used to test for antibiotic resistance in bacteria
It allows for

Answer 3

multiple antibiotics to be tested at once

Question 4

apparatus

Sterile agar plates
The agar can be made sterile by boiling
Diluted bacterial broth with a concentration of 1 x 108 CFU mm-3
Colony-forming unit (CFU): a live bacterial cell that is able to divide and form a colony on the agar plate
Multiple different antibiotic solutions of a standard concentration
Paper disks
Pipettes
Spreaders
Bunsen burner
Gloves
Goggles
Incubator

Question 5

step 1 of practical

Pre-soak paper discs in the different………

The different antibiotic solutions need to be the………………so that the effects of the different antibiotics can be compared

Answer 5

antibiotic solutions

same concentrations

Question 6

step2

Spread a sample of the diluted bacterial broth onto the surface of

Answer 6

the sterile agar plate

Question 7

step 3
Lightly press the paper discs onto the surface of the agar

Make sure the discs are……………

They should not be touching the edges of

Answer 7

the plate or any other discs

Question 8

step 4 Keep the agar plate in the incubator………….

the incubator……….

Answer 8

overnight

The incubator maintains an optimum temperature for bacterial growth

Question 9

Remove the agar plate from the incubator and examine the results with the petri dish lid….

Answer 9

on