Agar plates should be incubated in an
inverted position to prevent condensation on the agar surface that could spread the inoculated organisms
.
Why are agar plates incubated upside down quizlet?
Why do we incubate the agar plates upside down? The agar plates were incubated upside down in
order to prevent the condensation formed on the lid from dripping thus drowning the colonies
.
Why should agar plates be incubated upside down?
Petri dishes need to be incubated upside-down to
lessen contamination risks from airborne particles landing on them
and to prevent the accumulation of water condensation that could disturb or compromise a culture.
What would happen if you put the agar gel plate in upside down?
The purpose of placing the plates upside down is
to prevent condensation from dripping down onto the agar surface which could then facilitate movement of organisms between colonies
.
Why is it important to invert the petri plates during incubation quizlet?
Why is it important to invert the petri plates during incubation?
Because moisture will condense on the surface of the agar and cause confluent growth instead of isolated colonies
.
What is the difference between a broth and slant?
Pure broth cultures contain a liquid media, while slant cultures
contain a semi-solid media
. The substance used to make the media of a slant culture…
Why do we put the plates in the incubators at 25 C and not higher?
Inoculated agar plates are incubated at 25°C in school laboratories for no more than 24–48 hours. This
encourages growth of the culture without growing human pathogens which thrive at body temperature
(37°C).
What happens if you incubate bacteria too long?
If a bacterial culture is left in the same media for too long,
the cells use up the available nutrients, excrete toxic metabolites, and eventually the entire population will die
. Thus bacterial cultures must be periodically transferred, or subcultured, to new media to keep the bacterial population growing.
Why are agar plates incubated at 30 degrees?
Fungi grow more successfully at lower temperatures.
Do not incubate at human
body temperature (or above 30 °C) – this reduces the risk of culturing microbes that are pathogens to humans.
What would happen to plates poured with agar that is too hot?
If the agar is too hot,
the bacteria in the sample may be killed
. If the agar is too cool, the medium may be lumpy once solidified.
Is it always necessary to parafilm all agar plates?
It is not necessary to seal
with part in as long as the petri dish is in good condition as produced by the manufacturer.
At what temp does agar melt?
Solid agar melts at
about100°C
; liquid agar solidifies at about 42°C. Because microbes are ubiquitously distributed in the environment, during the preparation of any culture medium, bacteria are introduced from many sources such as glassware, dry medium components, air, and so on.
What is the purpose of Subculturing?
Subculturing describes the transfer of microbes from one growth medium container, such as broth or agar, to another,
and allowing the microbes to grow
. Subculturing is also useful in keeping strains alive by transferring them to fresh growth medium.
Do all culture media need to be sterilized before?
When microbiological media has been made, it still
has to be sterilized because of microbial contamination from air, glassware, hands
, etc. Within a few hours there will be thousands of bacteria reproducing in the media so it has to be sterilized quickly before the microbes start using the nutrients up.
Why are agar plates incubated at 37 degrees?
Petri plates are filled with with agar, which feeds bacteria that are inoculated on the surface. Under the proper conditions (usually 37 degrees Celsius),
the bacteria will consume the agar as food and grow into colonies called colony forming units (CFU’s)
.
What is the advantage of using broth?
When cooked, chicken broth
helps sooth the body with heat, hydration, and nutrients
. Chicken broth is rich with vitamins and minerals, which are useful against common ailments like the common cold, the flu, and food poisoning. The broth also provides several other notable health benefits, such as: Weight management.
