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38 Cards in this Set

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Lec 5
- Law of growth
- dN/dt=kN
N = population
t = time
k = specific growth rate con.
Lec 5
- characteristics of K
in the law of growth
expermintal calc
- k=2.303(log N-log No)/t

if any parameter changes,
- k must be recalculated
Lec 5
- Methods to measure
microbial growth
(name them)
- turbidity (light scatter)
- counting chamber
- electronic particle counter
- FACS (fluorescent act. cell sort)
- Dilute and plate
Lec 5
- Counting Chamber
characteristics
- Used to get population (N)
- works like hemocytometer
- pros
- counts differentially
(by shape or stain)
- immediate answers
- easy and somewhat quick
- cons
- need 100x microscope
- counts both dead & live
Lec 5
- Electronic Counting chamber
characteristics
- uses change in conductivity to
measure (N)
- utilized after getting N by
other count method
- utilizes electrodes and a
conductive solution
- Pros
- once you have N, you dont
need to count
- a drop in current equals
presence of microbes
Lec 5
- Turbidity and Optical
Densities (O.D.)
characteristics
- spectrophotometer is used to
measure O.D.
- Light in minus light out = OD
- measures amount of light
scattering (cloudiness)
- Pros
- easy and quick
- cons
- requires spectrophotometer
- cant distinguish between
dead & live
Lec 5
- Dilute and Plate
characteristics
- used to verify other other
methods of microbe growth
- pros
- counts only live members
- used for anti-bio type
exp to measure viablity
- cons
- takes 24-48 hrs
Lec 5
- Dilute and Plate
- Why is this method used
for anti-biotic trials?
- can distinguish between
1 - slow growth or actual
killing
2 - really dead vs. stunned
Lec 5
- Growth Curve
- purpose
- measures pop vs. time over
some interval
- has 4 phases
- normally shows 2 results
1 - turbidity (light
scatter)
2 - Dilute and plate
Lec 5
- Growth Curve
- Lag Phase
- 1st phase
- Time before growth of
organisms
- may or may not be seen in lab
Lec 5
- Growth Curve
- Exponential Phase
- Law of Growth is used and
calculated for this phase
- proper calc of (k)are made
- population # increases
Lec 5
- Growth Curve
- Stationary Phase
- No growth takes place
- food is used up
- _____ exaggerates pop b/c it
counts dead pop as well
Lec 5
- Growth Curve
- Death Phase
- Population declines as
organisms die (no shit)
Lec 5
- Types of growth media
- What is a media
- Substance with which you grow
microbes/organisms
Lec 5
- Types of growth media
- Name them
- Defined Media
- Undefined Media
- Minimal Media
- Selective Media
- Differential Media
Lec 5
- Types of growth media
- Defined Media
- Media in which you can write
the chemical form. for all
ingredients
Lec 5
- Types of growth media
- Undefined Media
- Media in which 1 or more
ingredients you cannot
write a chem. formula
Lec 5
- Types of growth media
- Minimal Media
- Media in which the minimal
amount of chemicals is used
for microbes to grow
Lec 5
- Types of growth media
- Selective Media
- Media in which chemicals are
used to allow certain microbes
to grow while denying growth
for others (selection)
Lec 5
- Types of growth media
- Differential Media
- Media in which multiple
microbes can grow, but are
differentiable by
phenotype
Lec 5
- Classification by Physical
Parameters
- List the parameters
- Temperature
- Hydrostatic Pressure
- Osmotic Strength
- pH
Lec 5
- Classification by Physical
Parameters
- Temperature
- characteristics
- Utilizes Arrhenius Plot for
growth curve analysis
- Greater the (k)= higher growth
rate
- (k)max = summit of curve
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles
- Love Cold
- Ideal K = 4 C or refridge temp
- Can grow in cold b/c lots of
PUFA (polyunsat fatty acids)
- keeps membranes fluid at
cooler temps
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles
- facultative
- Can grow in the cold, but
would rather have warm
- optimal growth >20 C
- AKA Psychrotrophs
Lec 5
- Classification by Physical
Parameters
- Temperature
- Psychrophiles
- Obligate
- Must grow in cold temps
- optimal growth <20 C
Lec 5
- Classification by Physical
Parameters
- Temperature
- Mesophiles
- Middle temp, like inside body
- Ideal K = 37 C
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles
- Hot loving
- Ideal K = 60
Lec 5
- Classification by Physical
Parameters
- Temperature
- Hyperthermophiles
- exteme heat loving
- Ideal K = 88 (106???)
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles
- Importance of
thermophiles
- Enzymes very important for
microbio industry
- Provides Taq DNA Polymerase
for PCR reactions
- it increase amount of DNA
Lec 5
- Classification by Physical
Parameters
- Temperature
- Thermophiles
- How did they
survive?
- Developed 1st in Evolution
- Utilizes Amino Acids with more
Ionic bonds (stronger DNA)
- Membranes has C40 lipids
- single layer membrane
- high in sat fatty acids
- DNA is positive super coiled
Lec 5
- Classification by Physical
Parameters
- Hydrostatic Pressure
- Barophiles
- Love/need high pressure
- high Hydrostatic Pressure
(Deep Sea)
- Cell membrane is 100%
permeable to H2O
- pres. inside= pres.
outside
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- characteristics
- microbes that can grow in
varying concentrations of Salt
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- Osmotolerant
- microbe that can grow in wide degrees of osmotic pressure (salt content)
Lec 5
- Classification by Physical
Parameters
- Osmotic Pressure
- Halophiles
- microbes that require high salt content to grow
Lec 5
- Classification by Physical
Parameters
- pH
- Characteristics
- microbes that grow at varying
degrees of pH
Lec 5
- Classification by Physical
Parameters
- pH
- Acidophile
- pH = 0 to 5.5
Lec 5
- Classification by Physical
Parameters
- pH
- Neutrophile
- pH = 5.5 to 8.0
Lec 5
- Classification by Physical
Parameters
- pH
- Alkalophile
- pH = 8.5 to 11.5