Ch 5 - Microbial Growth Flashcards
cell division following enlargement of a cell to twice its minimum size
Binary fission
forms ring around center of cell
ftsZ
major shape-determining factor in prokaryotes
mreB
Forms simple cytoskeleton in Bacteria and probably Archaea
mreB
Localizes synthesis of new peptidoglycan and other cell wall components to specific locations along the cylinder of a rod-shaped cell during growth
mreB
in _____, cell walls grow in opposite directions outward from the FtsZ ring
Cocci
in _________, growth occurs at several points along length of the cell
rod-shaped cells
where two daughter cells begin to separate
septum
these are the most important proteins in cell division
FTS Proteins (ftsZ, in particular)
small openings in the wall are created by _______.
autolysins
junction between new and old peptidoglycan
wall band
next to last step in cell wall synthesis
Transglycosylation
final step in cell wall synthesis
Transpeptidation
Forms the carbohydrate cross-links
transglycosylation
Forms the peptide cross-links between muramic acid residues in adjacent glycan chains
transpeptidation
time required for microbial cells to double in number
generation time
growth of a microbial population in which cell numbers double within a specific time interval
exponential growth
a closed-system microbial culture of fixed volume
batch culture
an open-system microbial culture of fixed volume
continuous culture
most common type of continuous culture device
chemostat
in ______ culture, it is impossible to independently control both growth parameters
batch
uses laser beams, fluorescent dyes, and electronics to measure # of live and dead cells
flow cytometry
the (higher/lower) the Opitical Density in a spectrophotometer reading, the more bacterial growth
higher
the minimum, optimum, and maximum temperatures at which an organism grows
cardinal temperatures
low temperature microorganisms
psychrophile
midrange temperature microorganisms
mesophile
high temperature microorganisms
thermophile
very high temperature microorganisms
Hyperthermophile
organisms that grow best at low pH (<6)
acidophiles
organisms that grow best at high pH (>9)
alkaliphiles
organisms that grow best at reduced water potential
halophiles
organisms that require high levels (15–30%) of NaCl for growth
extreme halophiles
organisms that can tolerate some reduction in water activity of environment but generally grow best in the absence of the added solute
halotolerant
organisms that can tolerate some reduction in water activity of environment but generally grow best in the absence of the added solute
aerobes
do not require oxygen and may even be killed by exposure
anaerobes
can live with or without oxygen
facultative organisms
can tolerate oxygen and grow in its presence even though they cannot use it
aerotolerant anaerobes
can use oxygen only when it is present at levels reduced from that in air
microaerophiles
Complex medium that separates microbes based on oxygen requirements
thioglycolate broth
