Question

Growth Curves and Logistic Equation

You are working with a culture of Chinese Hamster Ovary Cells (CHO). Given:

-Specific growth rate=1.2 days^-1

-Initial cell population=10^5 cells

-Maximum population that can be sustained by the environment=10^8 cells

-There is a lag phase, 0 days<t<1 days, during which no growth occurs. Exponential growth begins at t=1 day.

Write an equation that describes the number of cells as a function of time. Plot cell concentration vs time on a semilog plot. On your graph, label the following regions: lag phase, exponential growth, stationary phase.

Answer 1

Lag phase from day 0 to day 4

Exponential phase from day 5 to 10

Stationary phase from day 11 to day 14.

And this graph was plotted using above information such as specific growth rate and initial count final count etc.

dX/dT=uX where u is specific growth rate and X is number of cells at t time

another equation between bacterial numbers and time

G =    t   
       3.3 log b/B

where

t = time interval in hours or minutes

B = number of bacteria at the beginning of a time interval

b = number of bacteria at the end of the time interval

G=generation time