bacterial culture growth curve Flashcards
observed when microbes are cultivated in batch culture=
closed vessel, limited nutrients
usually plotted as
logarithm of cell number vs time
has 4 phases
Lag
Exponential (Log)
Stationary
Death (Decline)
Lag phase
no increase in cell numbers
Exponential (Log)
maximal rate of division and population growth
Stationary
population growth ceases - death rate = division
death (decline)
population number decreases
in the LAG PHASE cells are
synthesizing new components
in the LAG PHASE cells are preparing for
exponential phase (dedicated growth)
in the LAG PHASE cells are replenishing
spent materials, making new ones
in the LAG PHASE cells are adapting to
new medium or other conditions
in the LAG PHASE cells are repairing
damage
the LAG PHASE varies in
length (can be so short, its undectable)
exponential phase aka
log phase
in the EXPONENTIAL PHASE (LOG) rate of growth is
constant
in the EXPONENTIAL PHASE (LOG) the population is most
uniform in terms of chemical & physical properties
in the EXPONENTIAL PHASE (LOG) all cells are dedicated to
growth
in the EXPONENTIAL PHASE (LOG) bacteria are MOST
susceptible to antibiotics
in the STATIONARY PHASE total number of
viable cells remans constant
in the STATIONARY PHASE no net growth in number of cells because
reproductive rate equals death rate
in the STATIONARY PHASE as many cells dying as being
replicated
in the STATIONARY PHASE cells are changing to become more
resistant to harsh conditions
in the STATIONARY PHASE bacteria are MOST
resistant to antimicrobials
why enter stationary phase?
inhospitable environement
low nutrients/O2
high wastes or population density