ch 4 lab Flashcards
(25 cards)
inoculated
introduced
contaminants
unwanted microbes
Aseptic technique
used to exclude contaminants
sterilized
rendered free of all life
Agar slants
test tubes containing solid culture media that were left at an angle while the agar solidified
Broth cultures
provide large numbers of bacteria in a small space and are easily transported
agar deep
solidified agar at the bottom of a test tube
inoculating loop
noncorroding nichrome wire attached to an insulated handle is bend into a loop at the end of the wire
inoculating needle
when the noncorroding nichrome wire is straight at the end
what is the disinfectant used in your lab
heat
why should the entire wire get red
to kill bacteria
why are we not suppose to set down the cap of the test tubes
it can get bacteria on it
why must the loop be cooled after it is sterilized
because the heat will kill the bacteria if used too soon
can you determine whether a broth culture is pure(all one species) by visually inspecting it without a microscope? an agar deep? an agar slant?
no no no
when is a loop preferable for transferring bacteria?
when you need to streak the loop back and forth across the surface of the agar
when is a needle preferable for transferring bacteria
when microorganisms have to be transferred into a tube
what other methods can be used to determine motility?
the wet mount, the hanging drop method, and culturing method using a semisolid medium
what is the primary use of slants?
provide a solid growth site, easy to store & transport
what is the primary use of deeps?
to grow bacteria that need less oxygen than is present on the surface of the medium
what is the primary use of broths?
provide large numbers of bacteria in a small space
for a bacterium what is the evolutionary advantage to forming a pellicle in a liquid medium?
so that the bacterium can keep its shape and continue to survive in its environment because otherwise it would die
how can you tell that the media provided for exercise 4 were sterile?
control
what is the different between growing bacteria in a broth culture and slant culture?
in broth culture there are a large number of bacteria in a small space and in slant culture there is more room for the bacteria to grow
what does autoclaving accomplish?
kill microbes
