MIDTERM Flashcards
a medium that contains living microbes is called a
culture
a pure culture is
a culture that contains a single species
what are broths used for
grow microbes when fresh cultures or large number of cells are required
agar slats are used for
grow stock cultures that can be refrigerated after incubation
plated media are used for
obtaining isolation of species
a mixed culture is said to be
microbial culture made of two or more species
_______ contains only a single species
pure culture
commonly used isolation technique is
streak plate
______ substances designed to reduce the number of pathogen on a surface liquid or living tissue
germicide
germicides used on surfaces or in liquid are
disinfectants
antiseptics are
germicides designed for use on living tissue
a wet mount preparation is made by
placing specimen in drop of water on microscope slide and covering it with cover glass
motility often can be observed at
low or high dry magnification
hanging drop preparation allows for
longer observation of specimen because it does not dry out as quickly
the primary stain in gram stain is
crystal violet
what is purpose of iodine
mordant to enhance crystal violet staining by forming crystal violet iodine complex
what follows after iodine added
decolorization
gram positive cells are what color
purple
gram negative cells are what color
red/pink
gram negative cells can be colorized by
counterstain safranin
what does phenol red indicate
if fermentation with an acid end product has taken place by chains color as the pH changes
what grows on MSA (mannitol salt agar)
most staphylococci
staphylococcus aureus ferments
mannitol
the oxidation fermentation test is designed to
differentiate bacteria on basis of fermentation or oxidative metabolism of carboyhydrates
In OF test oxidative organism oxidize carbs to
CO2 H2O and energy
oxidase test is designed to identify
the presence of cytochrome c oxidase
a positive oxidase test gives the result
dark blue purple color
what ETC molecules are unable to donate protons
flavoproteins, iron-sulfur proteins, and cytochromes
what enzyme converts superoxide radicals to hydrogen peroxide
superoxide dismutase
catalase converts
hydrogen peroxide to water and O2
a positive catalase test gives what result
bubbles
negative catalase test gives what result
no bubbles
what gives chromogen its color
chromophore
