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Exponential Growth and Decay

The growth (decay) of bacteria colonies can be modeled using exponential functions. For example, one type of bacteria commonly used in research is Escherichia coli (also known as E. coli), a bacteria residing in the human digestive system. During the growth phase, approximately 12 hours, of E. coli the colony grows exponentially. For practicality, bacteria colonies are measured by mass rather than the number of cells present. The equation used to represent growth is


where tex2html_wrap_inline234 is the initial mass of the bacteria population, r is the growth rate and M is the mass of the population after time t.

Roxanne Tisch
Tue Sep 24 13:59:38 EDT 1996