ch9 Flashcards
The replication of DNA starts at a location on the circular chromosome called
origin of replication
Process of cytokinesis and cell division is directed by a protein called
FtsZ
Divisome function
produce peptidoglycan wall and build a septum to divide daughter cells
lag phase
no increase in number of living cells
log phase
exponential increase in living cells
stationary phase
plateau in number of living cells, rate of division and death is equal
death/decline phase
exponential decrease in living cells
beginning of growth curve
inoculum
inoculum is added to a fresh
culture medium
sporulation and secondary metabolite productions are associated with what phase
stationary
duration of lag phase depends on
- species and genetic makeup
- composition of medium
- size of original inoculum
secondary stain
stains if cytoplasmic membrane is damaged (dead)
primary stain
stains both live and dead
chemostat
maintain a continuous culture with nutrients supplied
pH indicator that changes color from red to yellow when
lactose is fermented
microorganisms grow mainly in
biofilms: complex ecosystems that form on a variety of environmental surfaces
biofilms secrete an extracellular matrix called
extracellular polymeric substances
free-floating microbial
planktonic
cells in a biofilm coordinate their activities in response to environmental stimuli
quorum sensing
quorum sensing enables microorganisms to detect cell density through release and binding of molecules called
autoinducers
pathogens embedded within biofilms exhibit
a higher resistance to antibiotics than their free-floating counterparts
reactive oxygen species (ROS)
unstable ions and molecules derived from partial reduction of oxygen
Obligate aerobes
cant grow without abundant supply of oxygen
Aerotolerant anaerobes
don’t use oxygen
