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40 Cards in this Set

  • Front
  • Back
exponential growth
with optimal growth conditions the number of cells in a culture increases exponentially.
generation time
time it takes for cells to double in a culture
typical growth
#cells(y) vs time(x)..
arithmetic= exponential backwards "L"
# of cell generations(N)
typical growth phases of batch cultures
(od=optical density, right hand side of graph from .1-1)
exponential:log=5-8, od=.15-.65
stationary:log=8, od=.65
death:log=8-6.5, od=.65-.45
continuous cultures (chemostat)
growth rate is controlled by the rate of nutrient supply and the effluent of cells. The population is maintained in a steady state (#cells/ml doesn't change)
relationship bw doubling time and dilution rate in a chemostat
steady-state bacterial(y) vs
dilution rate(x) vs
doubling time(h) [right side]
doubling time=dec expon. "L"
bacterial []= rounded square
steady-state=leveled top of square
water activity a(w)
ratio of vapor pressure of the air in equilibrium of a solute in water/vapor pressure of pure water. varies from 1-0.
water activity examples
1 pure water spirillum
.995 human blood streptococ
.980 seawater vibrio
.750 salt lakes halococcus
.7 cereal,candy bisporus
compatible solutes
microorganisms grow in enviro's of low water activity they get water from increasing intracellular solutes by pumping is substance ions or synthesizing/acquiring organic compounds.
major solutes accumulated
glycine based for .97-.75
KCl for .75
glycerol .83-.61
carbohydrate-type solutes
sucrose: hex and pent

trehalose: two hex
alchohol-type solutes

mannitol:6C ends are CH2OH and middle 4 are CHOH
amino acid-type and related solutes
glycine betaine:5C, N-center with 3-CH3, 1-CH2 and 1-COO
ectoine:hex, 2N, 6C, 1 C=N
1 C=O, 2 total O, and S
growth indicators of oxygen[]
resazurin:redox indicator is pink when oxidized(indicates location of O2)
low agar thioglycolate broth: reduces O2 to H2O
growth responses to oxygen[]
obligate aerobe
oxygen sensitive aerobe
facultative aerobe
obligate aerobe: no ferment
O2 sensitive aer: @ bottom
facultative aer:respires and ferments (dense top, sparse bottom)
growth responses to oxygen []
aerotolerant anaerobe
oxic=top and anoxic=middle
micro:grows at low O2 only, gives 2 section at top tube
aerotoler:ferments only, gives even particle spread
anoxic jar and glove box
rxn in bag generates H2 and CO2, palladium catalyst used to drive the rxn 2H2 + O2 gives 2 H2O molecules.
Airlock can be evacuated and filled with O2-free gas (N2)
*process used to render a pdt or surface free of all viable organisms(spore/virus)
1.requires no damage to material during process or residue left that harms
sterilization with....
anti:inhibition or destruction of microorganisms in or on living tissues(skin,linings)
disinfect:reduction of viable organisms on or in a pdt or surface to a level specified as being acceptable
standardizing sterilization equipment and procedures....
decimal reduction, killing 90% cells=1 decimal reduction
(ie: a 3-decimal reduction means a survival of 10e-3 or .1% of the initial # of cells or spores used to determine the effectiveness of a sterilization procedure.
standardizing sterilization equipment and procedures
with gram + use autoclaves
decimal reduction times for the same mesophilic bacterium at different temperatures (log scaled)
survival fraction(y) vs time
y-intercept=100 and corresponding graphs are linear decreases (for 50deg the decimal reduction time is 40 min, 60 deg=13 min, and 70 deg=4 min)
comparison of the decimal reduction times at different temperatures for mesophile and thermophile
decimal reduction(y) vs temp
thermophile: high linear dec
mesophile: low linear dec
(they are parallel)
methods used for sterilization....
HEAT with pasteurization
(wet heat,steam @ sub-atomospheric) used to reduce the # of living organisms(disinfection) in perishables
methods used for sterilization....
HEAT with steam
in autoclaves(wet heat, steam above atomos P) used to kill all organisms and spores to sterilize equipment and liquids that dont decompose is exposed to high heat.
methods of sterilization...
HEAT with incineration
used for the complete destruction of biological material(hazardous chemicals)
methods of sterilization...
such as ethylene oxide and ozone, used to sterilize heat sensitive materials, particularly plastics(petris,gloves) and lensed instruments. [ethylene is most common, its highly flammable and used when air isn't present]
methods of sterilization...
for materials that dont resist heat(plastic,veggies,meat,gel,pacemakers) UV has little penetrance and used to disinfect surfaces.
radiation continued...
electron-magnetic radiation
xrays:penetrate pduced by e- collision from heat cathode with heavy-metal anode
e:pduced in linear accelerations are very effective with low penetrance
g-rays:pduced by decay, very effective
typical irradiation sterilizer
typical exposure rack containing (60)CO as a generator of g-rays
(has shielded chamber, conveyor belt, ionizing radiation source(60)CO)
radiation sensitivity of microorganisms and biological functions
(gram + ana and aero, gram - and gram +)
gram + anaerobic....3300-2400
gram + aerobic......600
gram -..............200
gram +..............1200
radiation sensitivity continued...
(gram - radiation resistant, mold, yeast virus)
(lethal human dose is 10Gy)
methods of sterilization....
membrane filters made from inert polymers(nylon,polycarbonate,nitrocellulose) sterilize chemical solns that dont resist heat. they dont reliably remove viruses.
filtration apparatus in many sizes
syringe:pre-sterilized disposable filter
lab continuous flow: pre-sterilized filtration unit
large in-line filter cartridge
industrial filtering unit
methods of sterilization...
disinfect water supplies(chlorine,ozone,Cu-S), surfaces(bleach), medical and dental tools(H2O2) and disinfectants(iodine solns).
[a wide variety of all]
water purification system
steps 1-3
1.sedimentation: remove sand, large particles
2.coagulation:form and remove floc with insoluable material/microo
3.filtration:remove all remaining particles(ino&orgo)
water purification systems
4.chlorination:kill remaining microorganisms growth of new inocula
6.distribution:finished water
water treatment systems
use a chlorine and a scale releasing agent
infectious disease outbreaks associated with drinking water in the USA
e.coli & jejuni....781
norwalk virus......356