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65 Cards in this Set

  • Front
  • Back
the increase in number of cells, not cell size
microbial growth
what is one physical requirement for growth
temperature
3 types of temperature
minimum
optimum
maximum
psychrotrops cause
food spoilage
most bacteria grow between pH
6.5 and 7.5
molds and yeasts grow between pH
5 and 6
acidophiles grow in
acidic environments
hyptertonic environments increase
salt or sugar
hypertonic environmnts cause
plasmolysis
extreme or obligate halophiles require
high osmotic pressure
facultative halophiles tolerate
high osmotic pressure
carbon: structural organic molecules use
energy source
chemoheterotrops use
organic carbon sources
autotrophs use
CO2
nitrogen is in
amino acids and proteins
some bacteria use
NH4+ or NO3-
a few bacteria use N2 in
nitrogen fixation
sulfur in amino acids is
thiamine and biotin
momost bacteria in both sulfur and nitrogen decompose
proteins
some bacteria use
SO42- or H2S
phosporus is in
DNA, RNA, ATP, and membranes
what is a source of phosphorus
PO43-
inorganic elements required in small amounts
trace elements
trace elements are usually as
enzyme cofactors
obligate aerobes
facultative anaerobes
obligate anaerobes
aerotolerant anaerobes
micro-aerophiles
types of oxygen (O2)
singlet oxygen is toxic because
02 boosted to a higher-energy state
superoxide free radicals goes through
superoxide dimultase
peroxide anion goes through
catalase
peroxide
toxic forms of oxygen
singlet oxygen
hydroxyl radical
singlet oxygen types
superoxide free radicals
peroxide anion
organic compounds are obtained from
the environment
what are some organic compounds
vitamins, amino acids, purines, and pyrimidines
nutrients prepared for microbial growth
culture medium
no living microbes
sterile
introduction of microbes into medium
inoculum
microbes growing in/on culture medium
culture
agar has complex
polysaccharide
what is used as a solidifying agent for culture media in
Petri plates, slates, and deeps
agar is generally not metabolized by
microbes
agar liquefies at
100*C
solidifies at
-40*C
exact chemical composition is known
chemically defined media
extracts and digests of yeast, meat or plants
complex media
types of complex media
nutrient broth & agar
reducing media contains chemicals that
combine 02
reducing media is heated to
drive off 02
heated to drive off 02
anaerobic jar
anaerobic chamber
require high CO2
capnophiles

candle jar
Co2-packet
suppress unwanted microbes and encourage desired microbes
selective media
make it easy to distinguish colonies of different microbes
differential media
encourages growth of desired microbe
enrichment media
contains only one species or strain
pure culture
a population of cells arising from a single cell or spore or from a group of attached cells
colony
a colony is often called a
colony-forming unit (CFU)
deep-freezing
-50*C to -95*C
lyophilization
freeze-drying

frozen (-54*C to-72*C) and deydrated in a vacuum
reproduction in prokaryotes
binary fission
budding
conidiospores
fragmentation of filaments
perform serial dilutions of a sample
plate counts
inoculate Petri plates from
serial dilutions
after incubation
count colones in plates that have 25-250 colonies
direct measurements of microbial growth
filtration
multiple tube MPN test
direct microscope count
capillary actions
count positive tubes and compare to statistical MPN table
multiple tube MPN test
how do you estimate bacterial numbers by indirect methods
turbidity

#of bacteria-ml or # of cells counted / volume
direct methods of measuring microbial growth
plate counts
filtration
MPN
direct microscopic count
dry weight
indirect method of measuring microbial growth
turbidity
metabolic activity
dry weight