1. Fill in the missing data from the table: (1point # of colonies l Total Diluti
ID: 205974 • Letter: 1
Question
1. Fill in the missing data from the table: (1point # of colonies l Total Dilution 1 CFU/ml A. 80 10-7 9x108 B. 10-7 8x108 C. 150 10-5 D. 10-6 7.5x107 7x10 108 E. 283 2.83x108 6x108 F. 1.11x106 5x108 G. 6.7x10 2. The scale to left is a log scale, and the scale to the right is a linear scale. I have labeled certain cardinal points. Plot the data from question 1 on these scales. Use the letters to indicate label the data on the scale. (2 points) t4x100 107, 3. If we can use spectrophotometer reading to calculate the CFU/ml for the growth curve, why didn't we use the spectrophotometers for the DRT curve? (1 point) 2x10 1x108 105Explanation / Answer
1. CFU/ml or colony forming units per ml is defined the number of viable bacterial cells in a culture. It is calculated by multiplying the number of cells counted on a culture plate multiplied by the dilution factor.
Hence the table can be filled up with this knowledge.
3. DRT or the Decimal reduction time curve is the time required to eliminate 90% or log1 of the exposed microorganisms at a given set of conditions. In case of CFU/ml, the spectrophotometer could be used because the turbidity measured is directly proportion to increase in viable colony/cell number. But, DRT is measure of time and the response is not directly proportional to the dose or increasing time. Hence spectrophotometer cannot be used to calculate DRT.
#No. of colonies Total Dilution CFU/ml A 80 10-7 8.0 x 108 B 55 10-7 5.5 x 108 C 150 10-5 1.5 x 107 D 75 10-6 7.5 x 107 E 283 10-6 2.83 x 108 F 111 10-4 1.11 x 106 G 67 10-5 6.7 x 106Related Questions
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