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microbial growth
n/a
25
Microbiology
Undergraduate 3
03/27/2013

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Term
memb gelling?
Definition
transport so slow that growth cant occur
Term
prot denaturation
Definition
collapse of cytoplasmic memb; thermal lysis
Term
obligate cold weather organism?-frozen lakes
Definition
psychrophiles
Term
organisms that have midrange temp optima; found in warm blooded animals, aquatic environments, temp and tropical latitudes
Definition
mesophiles
Term
organisms that grow under very hot and cold conditions
Definition
extremophiles
Term
tolerate fair temperatures, grow at warm temps better than cold, cause food spoilage
Definition
psychotrophs-psychrotolerant
Term
production of enzymes that function in the cold may be denatured when?
Definition
at moderate temps
Term
3 features that may provide more flexibility in life in the cold?
Definition
-more alpha helices tha beta sheets
-more polar and less hydrophobic AA
-fewer weak bonds
Term
modified cytoplasmic membranes?
Definition
have high unsaturated fatty acid content
Term
which groups has more AA that are charged?
Definition
psychrophiles
Term
mechanisms for comnbating low water activity in surrounding environment invlove increasing internal solute concentration by?
Definition
1.)pumping inorganic ions from environment
2.)synthesis or conc of organic solutes
Term
cmpds used by cells to counteract low water activity in surrounding evironment
Definition
compatible solutes
Term
halotolerant
Definition
can live with little water reduction, but live best in absence of added solute
Term
effect of oxygen on growth:
1.obligate aerobes?
2.facultative aerobes?
3.obligate anerobes?
4.aeroltolerant anaerobes?
5.microaerophiles?
Definition
1.grow best in oxygen
2. in oxygen or anaerobically
3.no oxygen
4.do not use oxyegn but can tolerate it
5.oxygen required for low concentration
Term
in toxic forms enzymes are present to?
Definition
neutralize most toxic oxygen species
Term
BINARY FISSION:
Definition
1.cell elongates, dna replicates
2.cell wall and plasma memb begin to form
3.cross wall forms separating the 2 dna copis
4.cell separates
Term
-generation time can be controlled by controlling?
-most bac have shorter gen times then?
-do prok or euk doube quicker?
-generation time is dependent on what 2 things?
Definition
-the environment
-euk microbes
-proks
-growth mediums and incubation conditions
Term
MICROBIAL GROWTH CYCLE
1.batch culture?
2.lag phase?
3.exponential phase?
4.stationary phase?
5.death phase?
Definition
1.closed system microbial culture of fixed volume
2.period b/t when culture is inoculated and growth begins
3.cells healthiest stage
4.growth rate of pop is 0;nutrient is used up or waste product of organism accumulates in medium
5.if incuation continues after stationary phase, the cells will eventually die
Term
1.continuous culture?
2.chemostat?
Definition
1.open sys microbial culture of fixed volume
2.most common type of continuous culture device
Term
both frowth rate and pop density of culture can be controlled independently and simultaneously by what 2 things?
Definition
1.dilution rate-rate at which fresh medium is pumped in and spent medium is pumped out
2.concentration of a limiting nutrient
Term
-growth rate in chemostat?
-growth yeild in chemostat?
Definition
-controlled by dilution
-controlled by conc of limitng nutrient
Term
BIOFILMS:
1.are what?
2.form?
3.share?
4.sheltered from harmful factors?
5. quorum sensing?
Definition
1.microbial communites
2.sime or hydrogels that is secreted by cells
3.nutrients
4.yes
5.sending in and out signals
Term
1.biofilms resistant to?
2.number of bac= # of cells counted/ vol of area counted
Definition
1. antiobiotics
2. microscopic count
Term
1.turbidity measures are?
2.count organisms individually?
3.to relate a direct cell count to a turbidity value, wht must occur?
Definition
1. indirect, rapid, and useful methods of measuring microbial growth(OD)
2.no
3.a standard curve must be established
Term
-direct correlation w/ bac cells and light passing through test tubes=?
Definition
-inversely related
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