Question

A laboratory technician performed 1:5 ditutions to a final concentration of 1:3125 Show the ratio of each tube. He then transferred 1 mL from each dilution tube on to a plate and got the follow numbers per plate. What was the concentration of the original sample? Plate 1 (undiluted) =>1000 Plate 2=>1000 Plate 3=584 colonies Plate 4=116 colonies Plate 5=23 colonies.

Answer 1

To calculate the concentration of the original sample, we can use the dilution factor and the number of colonies on each plate. By multiplying the number of colonies by the dilution factor, we can estimate the concentration of the original sample. The estimated concentration of the original sample in this case is approximately 3125 colonies/mL.

Step-by-step explanation:

The concentration of the original sample can be calculated by taking into account the dilution factor and the number of colonies on each plate. In this case, the technician performed 1:5 dilutions, resulting in a final dilution of 1:3125. The number of colonies on each plate can be used to estimate the concentration of the original sample. By multiplying the number of colonies on each plate by the dilution factor, we can find the concentration of the original sample as follows:

Undiluted Plate: 1000 colonies x 1:3125 = 3125 colonies/mL
Plate 2: 1000 colonies x 1:3125 = 3125 colonies/mL
Plate 3: 584 colonies x 1:3125 = 1825 colonies/mL
Plate 4: 116 colonies x 1:3125 = 363 colonies/mL
Plate 5: 23 colonies x 1:3125 = 73 colonies/mL

Therefore, the estimated concentration of the original sample is approximately 3125 colonies/mL.