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Microbial Growth
Test Two
70
Microbiology
Undergraduate 3
02/01/2013

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Term
What are the 4 chemical rxns that aid in microbial growth?
Definition
energy transformations, synthesis of monomers, polymerization of macromolecules, formation of cellular structures
Term
What is binary fission
Definition
starting with one cell that ends up into two daughter cells
Term
what are determinants of population growth?
Definition
growth rate, generation, generation time, exponential growth
Term
Exponential growth
Definition
phase of growth cycle where cells are moving at fastest growth
Term
Growth cycle of populations: lag phase characteristics (3)
Definition
seen with old inoculations, damaged cells, transfer from nutrient rich to nutrient poor media
Term
Growth cycle of populations: exponential phase characteristics (3)
Definition
cells in healthiest state, midexponential cells, rates of exponential growth can vary
Term
When does exponential growth tail off?
Definition
stationary phase
Term
What growth phase are nutrients limited?
Definition
stationary
Term
What growth phase is there a buildup of waste products?
Definition
the stationary phase
Term
What growth phase do you have no net increase or decrease in cell number?
Definition
stationary phase
Term
What growth phase do you have cryptic growth (and what is cryptic growth)
Definition
birth rate=death rate, stationary phase
Term
What growth phase do you have sur genes?
Definition
survival genes to conserve energy (stationary phase)
Term
What is the death phase?
Definition
more death than life --> net decrease in cells
Term
What are the 4 phases growth curve?
Definition
lag, exponential, stationary, death
Term
Which growth phase is the longest?
Definition
death
Term
Which growth phase is the shortest?
Definition
lag
Term
What are the three characteristics of direct microscopic count?
Definition
- dry or liquid methods
- counting chambers
- quick
Term
What are the disadvantages of direct microscopic counting? 5
Definition
1) cant distinguish dead from living
2) Small cells are difficult to see
3) precision is difficult to achieve
4) Phase contract for unstained specimens
5) not used with low density suspensions
Term
What is viable count?
Definition
plate count or colony count
Term
What type of count assumes there is only one cell per colony?
Definition
viable count
Term
What measurement of growth technique spreads cells across plate?
Definition
viable count
Term
what measurement of growth uses the pour plate method (and what is it)
Definition
viable count - it is having it on top of the agar plate
Term
what measurement of growth uses dilutions?
Definition
viable count
Term
What are the sources of error in viable count? 3
Definition
1) inoculum size, medium, and incubation conditions
2) Different growth rates
3) May underestimate numbers
Term
What are the advantages of viable count?
Definition
1) high sensitivity
2) select for different population
Term
Measurement of growth: turbidometric methods: what does it measure?
Definition
turbidity caused by a cell suspension (turbidity is proportion to cells present)
Term
Measurement of growth: turbidometric methods. What does a photometer measure?
Definition
Klett units *um what
Term
Measurement of growth: turbidometric methods - what does a spectrophotometer measure?
Definition
optical density
Term
Measurement of growth: turbidometric methods - what does it measure
Definition
unscattered light
Term
Define turbidity
Definition
proportional to cell numbers
Term
What type of measurement growth must you prepare a standard curve?
Definition
turbidometric methods
Term
what happens in a turbidity measurement?
Definition
scattering of light
Term
how is the bug in a continuous culture?
Definition
it stays in a steady state
Term
Continuous culture: batch culture
Definition
fixed volume of medium
Term
Continuous culture
Definition
flow system
Term
continuous culture: steady state
Definition
constant cell number and nutrient status
Term
continuous culture: chemostat
Definition
dilution rate, limiting nutrient
Term
TF: in a chemostat, you will have cultures in 'stationary' all the time
Definition
T
Term
Effect of environment on growth: temp; what are the three cardinal temperatures?
Definition
minimum, optimum, maximum
Term
Temp classes: phychrophile
Definition
4 degrees: polaromonas vacuolaa
Term
Temp classes: mesophile
Definition
39; escherichia coli
Term
Temp classes: thermophile
Definition
60; bacillus stearo-thermophilus
Term
Temp classes: hyperthermophile ( lower level )
Definition
88: thermococcus celer
Term
Temp classes: hyperthermophile ( higher level )
Definition
106: pyrolobus fumarii
Term
What temp class is archea?
Definition
hyperthermophile
Term
TF bacteria is more acid tolerant than bacteria
Definition
False, fungi is more acid tolerant
Term
What kind of bacteria are acidophiles?
Definition
acidophilic bacteria
Term
In an acidophile, what do membranes depend on?
Definition
low ph
Term
picrophilus oshimae optimum for pH and temp
Definition
.7 and 60 degrees
Term
Where do you find alkaliphiles
Definition
soda lakes and carbonate soils
Term
what supplies energy for transport and motility in an alkaliphile?
Definition
sodium gradient
Term
what is the internal pH of an organism, no matter what
Definition
neutral with relatively narrow range
Term
What is plasmolysis
Definition
cytoplasm shrinks away from cell wall
Term
What do halophiles require?
Definition
NaCl
Term
Osmophiles like
Definition
high sugar
Term
xerophiles like
Definition
very dry environments, they need to be able to rip nutrients from the H2O
Term
What do aerobes tolerate?
Definition
full O2 tensions
Term
What is Microaerophiles relationship with O2
Definition
(require O2 but does not need all O2)
Term
what is microaerophiles tolerance for o2?
Definition
less than 21%
Term
what microorganism has a limited capacity for respiration?
Definition
microaerophiles
Term
What is an aerotolerant anaerobe?
Definition
it is not killed by o2 but it wont grow in O2
Term
What is an obligate anaerobe?
Definition
Lives in the absence of air
Term
What is a facultative anaerobe?
Definition
makes ATP using aerobic respiration if air is present, if not it switches to fermentation
Term
What is required for aerobes?
Definition
aeration
Term
What require exclusion of O2
Definition
anaerobes
Term
4 points under "anaerobes require exclusion of O2"
Definition
- fill medium container completely\
- reducing agent
- anerobe jar
- anaerobic glove boxes
Term
Test tubes: what does an obligate anaerobe look like?
Definition
concentration at the bottom
Term
Test tubes: what does facultative look like?
Definition
dense concentration at top and sporatically spread throughout
Term
Test tubes: micro aerophile
Definition
density right at top
Term
Test tubes: aero tolerant
Definition
spread evenly throughout
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