### E.coli Growth Curve

## by Cyndi Gonzales

Submitted : Spring 2015

In bacteria, increases in number of cells are used as indicators of growth. Different phases exist in the growth cycle of bacteria. After bacteria had become adapted to its environment and specific enzymes have been synthesized to transport and metabolize the nutrients, an exponential growth phase occurs. Using a simulation software an initial amount of cells of *E.coli* were grew at 37°C, with a pH of 7 and the cell densities (number of cells/mL) were counted every 0.33 hours (*E.coli’s* generation time by binary fission) for a total of 3 hours. The growth rate of this exponential phase was derived from the slope of the graph of cell density vs. time. Then, Monod model of exponential growth was analyzed to determine the relationship between the growth rate and the nutrient concentration in the culture. Two limiting cases were analyzed, one in which the specific rate was dependent on the substrate, and the other in which it was independent of it.

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