Lesson 9: Principles of Bacterial Growth Flashcards
refers to increase in number of cells and not the size of cells.
bacterial/microbial growth
which the bacteria undergo asexual cell division to produce two daughter cells genetically identical to the parent cell
binary fusion
begins with DNA replication and segregation of nucleoids (distribution between the future daughter cells)
Cell division
composed mainly of __________ assembled in the middle of the cell
Z-ring
FtsZ polymers
recruits additional proteins that serve for septum formation and subsequent separation of the daughter cells
Z-ring
is the time required for a bacterium to give rise to two daughter cells under optimum conditions.
Generation Time
replicates and multiplies rapidly producing millions of cells within 24 hours.
bacterium
Microbial concentration can be measured in terms of?
(i) cell concentration
(ii) biomass concentration
the number of viable cells per unit volume of culture
cell concentration
dry weight of cells per unit volume of culture
biomass concentration
the number of bacteria at a given time can be estimated by performing a?
total count or viable count
denotes the total number of bacteria in the sample, irrespective of wether they are living or dead.
total count
this is done by counting the bacteria under the microscope using counting chamber or by comparing the growth with standard opacity tubes
total count
indicates the number of living or viable bacteria
viable count
series of sequential dilutions used to reduce a dense culture of cells to a more usable concentration
dilution method
number of colonies that grow after a suitable incubation time
plating method
represents the number of live cells in a bacterial population over a period of time
bacterial growth curve
the time between inoculation and and beginning of multiplication. in this phase, the inoculated bacteria become acclimatized to the environment, switch on various enzymes, and adjust to the environmental temperature and atmospheric conditions. There is increase in size bacteria but no appreciable increase in number of bacterial cells
lag phase
this phase is characterised by rapid exponential cell growth of bacteria at their maximum rate.
log phase
are small and uniformly stained
bacterial cells