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A culture containing a single unadulterated species of cells is called a
Pure Culture
a liquid medium lacks a solidifying agent called a
broth medium
a broth medium supplemented with a solidifying agent called ______ results in a solid or semisolid medium.
agar
serves as an excellent solidifying agent because it liquefies at 100 degrees Celsius and solidifies at 40 degrees Celsius.
Agar
A completely solid medium requires an agar concentration of about 1.5 to 1.8%. A concentration of less than 1% agar results in a A concentration of
semisolid medium
Each colony is a cluster of cells that originates from the multiplication of a single cell and represents the growth of a single species of microorganism. Such a defined and well-isolated colony is a
pure culture
While in the liquefied state, solid media can be placed in test tubes, which are then allowed to cool and harden in a slanted position, producing _____________. These are useful for maintaining pure cultures.
agar slants
are used primarily for the study of the gaseous requirements of microorganisms.
Agar deep tubes
Agar deep tubes may be liquefied in a boiling water bath and poured into Petri dishes, producing ___________, which provide large surface areas for the isolation and study of microorganisms.
agar plates
The process of rendering a medium or material free of all forms of life.
Sterilization
Why are petri dishes incubated in an inverted position (top down) after inoculation?
To prevent condensation that forms on the cover during solidification from dropping down onto the surface of the hardened agar.
Microorganisms must be transferred from one vessel to another or from stock cultures to various media for maintenance and study. Such a transfer is called _____________ and must be carried out under sterile conditions to prevent possible contamination.
Subculturing
The microorganisms or other material used in an oculation
Inoculum
dispensed to previously sterilized dishes from molten agar deep tubes containing 15-20ml of medium
sterile medium
a shallow glass or plastic cylindrical dish that is use to culture cells or grow bacteria
Petri dishes
when agar is filled and solidifies in petri dishes
petri plate
is one prepared from purified ingredients and therefore whose exact composition is known
chemically defined media
an organism that has complex nutritional requirements. That grows only in a specially fortified artificial culture media under specific culture conditions.
Fastidious Organisms
consequently able to support the growth of more fastidious microorganisms that can simple non-synthetic medium
complex media
designed to suppress the growth of some microorganisms while allowing the growth of others (i.e., they select for certain microbes)
Selective Media
allow the growth of more than one microorganism of interest but with morphologically distinguishable colonies.
Differential Media
preprepared (or equivalent) media to which additional growth factors have been added.
Enrichment Media
If nothing grew from one or more of your environmental samples, does that mean that area you swabbed was really sterile?
No, it can be something that recently sterilized or it can be a virus, or probably we didn't collect enough specimen.
Why do incubators in clinical laboratories commonly operate at 35-37 degrees Celsius?
the same as our body temperature
what is the function of the chemical agar in solid media?
Chemical agar is a solidifying agent that bacteria can grow on.
What is bacterial colony?
many, many cell that grows from one cell
Why do we use agar instead of other chemicals such as gelatin of starch?
Agar serves as an excellent solidifying agent because it liquefies at 100 degrees Celsius and solidifies at 40 Degrees Celsius. Because of this properties, organisms, especially pathogens, can be cultivated at temp. of 37.5 Degrees Celsius or slightly higher without fear of the medium liquefying.
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