Microbiology quiz 2 Flashcards
spectrophotometer
Separates and measures spectral
components of a physical
phenomenon
spectral components are
mixed
For bacterial growth you use
OD600
An OD measurement characterizes
the amount of light that is lost due to
scattering and absorption at a given
wavelength
mechanisms of action components
light source, collimater, monochromator, wavelength selector, saple solution, detector, digital day os display
measure od flask at ____ min intervals
15
protocol for growth
e.coli grown overnight 37 and 25 degrees in flasks. culture diluted 1:100
measure flask every 15 min
record results
plot graph and determine generation time and growth rate
label various phases of growth
bacterial growth phases
lag->log->stationary->death
knowing bacterial growth phaes helps
undertsna dpopulation dynamics, and population contrl of infectious diseases, food preservation, spoilage
where is viabl count on graph
gowth area
Lag phase
interval between inoculation of a
culture and beginning of growth
growth can begin
Exponential phase
cells growth explods
double time
Doubling Time:
X8 – X4 = 14 - 8 = 6 hours
look at left side and see how ong it takes to dohble then subrtract bottom numbers
in Stationary phase Either an
essential nutrient is used up or waste products accumulate
Death phase
If incubation continues after cells reach
stationary phase, the cells will
eventually die
viable cells after death remain for
months or years
lag phase is the time needed
for biosynthesis of new enzymes and to produce required metabolites before
in stationary phase mtabolism
Metabolism continues at greatly reduced rate
mechanism of action measures
Measures the intensity of
light that passes through a
sample
the death phase is slower then the
exponential growth phase
in stationary phase the growth rate of population is
zero
why is there no growth in stationary phase
Some cells grow while others die, balancing each other
