Chapter 5

ruriwojo's version from 2015-06-16 04:48


Question Answer
: Increase in the # of cellsGrowth
: cell division following enlargement of a cell to twice its minimum sizeBinary Fission
: time required for microbial cells to double in numberGeneration Time
() protein mediates separation of chromosomes to daughter cellsFtsK
() proteins are essential for cell division in all prokaryotesFts Proteins
: is the final step in cell wall synthesisTranspeptidation
Transpeptidation can be inhibited by the antibiotic calledpenicillin
: Growth of a microbial population in which cell numbers double within a specific time intervalExponential Growth
: is a closed-system microbial culture of fixed volumeBatch culture
Typical growth curve for population of cells grown in a closed system is characterized by four phases. What are they?1.) Lag Phase 2.) Exponential Phase 3.) Stationary Phase 4.) Death Phase
During this phase, cells are adapting to new conditionsLag Phase
During this phase, the nutrients that have been depleted or toxic substances build-upStationary Phase
This phase is the interval between when a culture is inoculated and when growth begins.Lag Phase
During this phase, cells are typically in the healthiest stateExponential Phase
During this rate, the growth rate of population is zero, due to either an essential nutrient is used up or waste product of the organism accumulates in the mediumStationary Phase
In this phase, if incubation continues after cells reach stationary phase, the cells will eventually dieDeath Phase
Generation time can only be calculated during () phaseExponential Phase
: an open-system microbial culture of fixed volumeContinuous Culture
: most common type of continuous culture deviceChemostat
In a chemostat, both growth rate and population density of culture can be controlled independently and simultaneously by () and ()Dilution rate and Concentration
In a chemostat, the growth rate is controlled by:Dilution Rate
In a chemostat, the growth yield (cell #/mL) is controlled by the:Concentration of the limiting nutrient
In a () culture, growth conditions are constantly changing; it is impossible to independently control both growth parametersBatch Culture
Microbial cells can be enumerated by microscopic observations with a ()counting chamber
(): measurement of living, reproducing populationViable cell counts (plate counts)
Two man ways to perform plate counts are1.) Spread-Plate method 2.) Pour-Plate method
Turbidimetric Method is indirect, rapid, and useful meted of measuring microbial growth. It is most often measured with a ()Spectrophotometer
() ARE a major environmental factor controlling microbial growthTemperature, pH
() temperatures are the minimum, optimum, and maximum temperatures at which an organism growsCardinal Temperatures
(): organisms that have midrange temperature optimaMesophiles
(): Organisms that grow under very hot or very cold conditionsExtremeophiles
(): Organisms with cold temperature optima that inhabit permanently in cold environmentsPsychrophiles
(): Organisms that can grow at 0C but have optima of 20C to 40C and more widely distributed in nature than psychrophilesPsychrophiles
Above ~65C, only () life forms existPROKARYOTIC
Some organisms have evolved to grow best at low or high pH, but most organisms grow best between pH 6 and 8. These are calledNeutrophiles
Microbial culture media typically contain () to maintain constant pHBuffers