BIOL 3150 LAB PRACTICAL 1 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
ways to avoid contamination
- clean work surfaces, cleaning workstation and washing hands before and after
experiments
- proper aseptic technique applied (flaming loop after each bacterial sample, heating lip
of each tube before/after opening tube, etc)
- avoid touching the lip of a tube with a loop which contains a bacterial sample
why agitate a broth culture before obtaining a sample
to ensure that the bacteria, which was once settled at the bottom of the broth, is mixed
throughout the sample
broth culture
provide large numbers of bacteria in a small space and are easily transported
slant culture
used to store already purified cultures for extended periods of time
- can be sub-cultured to broths or new slants.
agar plate culture
large surface area which allows for the fast drying of bacteria
- good for isolation
why are slants used to store bacterial cultures
they allow for bacteria to grow slow and live much longer
how to cool an inoculation loop
, placing the face of the loop on an uninoculated area within the plate or slant
- must be done prior to removing any bacterial sample to ensure you do not kill the
bacteria you are sampling
petri dish to broth
- label sterile broth with initials, date, and name of organism
- heat inoculating loop until red hot
- lift and use lid of petri dish as shield from contamination
- touching the inoculating loop to an uninoculated portion of the plate to cool
- gently touch the loop to some growth and collect a small amount
- remove loop and replace lid of petri dish
- remove lid to broth, heat mouth of tube while keeping it at an angle to avoid
contamination
- insert loop into sterile broth and mix gently, tapping the loop's face on the inside of
tube before removing the loop from the tube (to remove film within the loop)
- reheat mouth of tube at angle and replace lid to broth
- flame inoculating loop from base to tip until red hot
why streak for a culture
to produce isolated colonies of an organism and better view characteristics of such
colonies
- samples can be taken from the isolated colonies
streak plate technique
- section the plate into quadrants
- begin with sample of organism on inoculating loop
WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
ways to avoid contamination
- clean work surfaces, cleaning workstation and washing hands before and after
experiments
- proper aseptic technique applied (flaming loop after each bacterial sample, heating lip
of each tube before/after opening tube, etc)
- avoid touching the lip of a tube with a loop which contains a bacterial sample
why agitate a broth culture before obtaining a sample
to ensure that the bacteria, which was once settled at the bottom of the broth, is mixed
throughout the sample
broth culture
provide large numbers of bacteria in a small space and are easily transported
slant culture
used to store already purified cultures for extended periods of time
- can be sub-cultured to broths or new slants.
agar plate culture
large surface area which allows for the fast drying of bacteria
- good for isolation
why are slants used to store bacterial cultures
they allow for bacteria to grow slow and live much longer
how to cool an inoculation loop
, placing the face of the loop on an uninoculated area within the plate or slant
- must be done prior to removing any bacterial sample to ensure you do not kill the
bacteria you are sampling
petri dish to broth
- label sterile broth with initials, date, and name of organism
- heat inoculating loop until red hot
- lift and use lid of petri dish as shield from contamination
- touching the inoculating loop to an uninoculated portion of the plate to cool
- gently touch the loop to some growth and collect a small amount
- remove loop and replace lid of petri dish
- remove lid to broth, heat mouth of tube while keeping it at an angle to avoid
contamination
- insert loop into sterile broth and mix gently, tapping the loop's face on the inside of
tube before removing the loop from the tube (to remove film within the loop)
- reheat mouth of tube at angle and replace lid to broth
- flame inoculating loop from base to tip until red hot
why streak for a culture
to produce isolated colonies of an organism and better view characteristics of such
colonies
- samples can be taken from the isolated colonies
streak plate technique
- section the plate into quadrants
- begin with sample of organism on inoculating loop
