Question

The adaptation phase for the E. coli culture lasted

A culture of E. coli was grown on suitable culture media; aliquots of the culture were serially diluted and spread plated aseptically on agar plate media at the times indicated in the table below. Upon overnight incubation at 37°C, colonies appeared and viable counts were colleted and displayed below. Hours 0 Viable Counts (CFU/mL) 2 .00 x 107 2.10 x 107 2.30 x 107 3.25 x 107 6.60 x 107 1.40 x 108 2.92 x 10 6.10 x 10 1.10 x 10' 1.23 x 10° 1.30 x 10° 8 10 Plot the data using Excel and label all axes and clarify the scales used. Submit the graphs to your instructor by saving your original excel document with your name and uploading it to dropbox. Indicate all growth phases observed for this E. coli culture. Please ensure that you include your name in the Excel file as unnamed files will not be graded. Please also ensure that you include the data in the Excel document for reference. You can use another sheet in excel to display the data and your second growth curve so that you only submit one excel document. No pictures or other forms of documents besides excel will be accepted for this assignment, so please adhere to the instructions as I will adhere to these instructions for grading. Again, in the text box for the assignment, please write a message so that you will open a grading box in mastering for me to be able to grade your curve. The latter indicates that you will have to place the data in the Excel cells so that you could generate the graph. Remember that I will not consider this extra credit assignment for grading if you do not provide me the Excel file with the indicated growth curves and I will assign a "0" grade for the whole extra credit assignment.

Answer 1

So, we have the data for plotting the growth curve of E. coli whose viable count is recorded starting from zero to 10 hours at an interval of one hour.

In order to plot the curve, we need to take the log values of the viable counts as these are too high and would fit better if we take a log instead of using actual numbers. The log values can be obtained in the excel sheet by typing "=log(cell#)" in the column next to the original values. "cell#" would mean we just choose the cell in which the original value is present.

Viable counts (CFU / mL)	Time (h)	log (CFU / mL)
2.00E+07	0	7.30
2.10E+07	1	7.32
2.30E+07	2	7.36
3.25E+07	3	7.51
6.60E+07	4	7.82
1.40E+08	5	8.15
2.92E+08	6	8.47
6.10E+08	7	8.79
1.10E+09	8	9.04
1.23E+09	9	9.09
1.30E+09	10	9.11

In the above table, the exponential value is represented as, for instance, "E+07" where E is for the base value of 10 and +07 represents the exponent, which in this case is 7. The first viable count value is given as 2.0E+07 to represent 2.0 * 10⁷. Similarly the other values are written down in similar format. A Line graph is plotted with the Time (h) in the X- axis and the log (CFU / mL) in the Y-axis. In the chart below, we can see a typical sigmoidal growth curve:

E. coli growth curve log (CFU / mL) 0 1 2 3 4 5 6 7 8 9 10 Time (h)

Under the "scale factor" option under "vertical axis" we need to choose "logarithmic scale" in order to get the sigmoidal curve.

The option to insert text is not available in google sheets, but the different phases (Lag, Log and Stationary) can be labeled in MS Excel using "Format > Insert > Text box"

Going by the chart, the values 0 to 2 hours represent the Lag phase, 3 to 8 hours represent the Log or exponential growth phase and 9 to 10 hours represent the Stationary phase.