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32 terms

Foundation in Microbiology chap. 3

STUDY
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Inoculation
Introduction of a sample into a container of media
Incubation
Under a condition that allows growth
Isolation
Seperating from one species to another
Liquid media examples
broth, milk, infusion
Liquid media
Water-based, do not solidigy at temperature above freezing; float easily
Semi-solid media
Contain an amount of solidified agent so that it's thickened but does not have to be firmed up to be solid; can be used to measured motility; localization of reaction
Solid media
Firm surface on which colonies of bacteria and fungi can grow
Semi-solid media examples
agar, gelatin
Solid media examples
agar
Solid liquidfiable media
Physical form change in response to temperature change
Solid nonliquidfiable media
Start out solid and stay solid; less use; not versatile
Nutrient broth
Liquid; beef extract and peptone
Nutrient agar
Solid; beef extract, peptone, agar
Agar
Complex polysaccharide isolated from red algae; solid at room temperature; liquidfies at boiling; does not resolidify until it cools to 42C; not digestable for most microbes
Synthetic media
Pure organic/inorganic compounds; chemically defined
Complex/nonsynthetic media
Has at least 1 ingredient that is not chemically definable
General purpose media
Grow a broad range of microbes, usually nonsynthetic
Enriched media
Complex organic substances such as blood serum, hemoglobin or special growth factors required by fastidious microbes
Selective media
Contain one or more agents that inhibit growth of some microbes and encourage growth of the desired microbes
Differential media
Allow growth of several types of microbes and displays visible differences among desired and undesired microbes
Reducing media
Contain a substance that absorb oxygen or slow penetration of oxygen into medium; used for growing anaerobic bacteria
Carbohydrate fermentation media
Contain sugar that can be fermented, converted to acids, and a pH indicator to show the reaction; basis for identifying bacteria and fungi
Pure culture
Contain of medium that grow only a single known species or type of microorganisms
Axenic culture
Is a pure culture, but it's free of other living things except the one being studied
Subculture
Make a second level culture from a well-isolated colony; a small amount of cells are transferred to a separate container and incubated
Mixed culture
Contain 2 or more easily differentiated species
Contaminated culture
Has unwanted microbes of uncertain identity
Magnification
Ability to enlarge objects
Rosolving power
Ability to show details
Bright-field microscopes
Most widely used; specimen is darker than surrounding field
Dark-field microscopes
Brightly illuminated specimens surrounded by dark fields
Phase contrast
Transforms subtle changes in light waves passing through the specimen into differences in light intensity; best for observing intracellular structures