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1. Dynamics of Prokaryotic Growth Chapter 4
2. Principles of Bacterial Growth Prokaryotic cells divide by binary fission
Cell growth is exponential
Doubling of population with each cell division
Generation time
Time it takes for population of cells to double
a.k.a doubling time
Varies among species
3. Bacterial numbers can be estimated using
the following equation:
Nt = N0 x 2n
(Nt ) number of cells in population
(N0 ) original number of cells in the population
(n) number of divisions
4. Bacterial Growth in Nature Bacteria can sense changes in their environment
Synthesize compounds useful for growth
Cells produce multicellular associations to increase survivability
5. Prokaryotes live in mixed communities
Many interactions are cooperative
Waste of one organism represents a nutrient for another
Some cells compete for nutrients
Synthesize toxic substance to inhibit growth of competitors
6. Bacterial Growth Under Laboratory Conditions Cells in laboratory grown in closed or batch system
No new input of nutrient and no release of waste
Contrast to open or continuous system
The population of cells in the culture increases in a
predictable manner before declining
Follows a pattern of stages called growth curve
7. The Growth Curve
8. Lag phase Number of cells does not increase Cells prepare for growth Log phase Period of exponential growth Doubling of population with each generation Produce primary metabolites Cells enter late log phase Synthesize secondary metabolites