Lecture 28: Microbial population growth Flashcards
smaller organisms can grow…
faster
binary fission is…
the process by which microorganism can replicate themselves
prokaryotes reproduce…
asexually
the process by which prokaryotes reproduce is…
binary fission
binary fission results in the formation of
two cells that are genetically identical
step 1 of binary fission:
chromosome replication begins
step 2 of binary fission:
one copy of the origin moves to each end of the cell
step 3 of binary fission:
replication finishes
step 4 of binary fission:
two daughter cells result
closed batch culture system refers to
a form of cell culturing
closed batch culture systems have a defined
supply of nutrients
once nutrients in a system have been used cells cannot
proliferate
what is the “lag phase” of microbial growth in a closed batch culture system
the time required to get biosynthetic reactions occurring
what is the “exponential phase (log phase)” of microbial growth in a closed batch culture system
- where cells are actively dividing and nothing is limiting growth
- population is doubling
what is the “stationary phase” of microbial growth in a closed batch culture system
- cells stop growing and cryptic growth is observed
cryptic growth is
when organisms survive by consuming lysed cell constituents of other dead cells within the culture
in the stationary phase the population is
dynamic
dynamic population means
there is an equilibrium between growing and dying cells
what is the “death phase” of microbial growth in a closed batch culture system
equilibrium between growing cells and dying cells is skewed towards death
growth rate is
a measure of the average to see what the population is doing
persisters are
insensitive to penicillin because they are dormant
penicillin stops bacteria by
preventing the cell wall forming meaning it falls apart during replication
three requirements for prokaryote growth
- carbon source
- energy source
- reducing power
carbon source for prokaryote growth is used as
building blocks for macromolecular synthesis
the energy source for prokaryote growth is used for
anabolic and catabolic reactions in the cell
reducing power is required for prokaryote growth to
carry energy/electrons
photoautotrophs
energy/carbon source
energy source = light
carbon source = harvest their own
chemoautotrophs
energy source = chemical compounds
carbon source = harvest their own
photoheterotrphs
energy source = light
carbon source = harvest carbon from other molecules
chemoheterotrophs
energy source = chemical compounds
carbon source = harvest their own from other molecules
