The total number of cells in a culture is counted using dye trypan blue and is found to be 3.8 x 106 cells/mL. The culture is diluted 1:22 and then 200μl seeded per well into a 96 well plate. What is the final cell density per well?

Ten grams of hamburger were added to 90 mL of sterile buffer. This was mixed well in a blender. One-tenth of amL of this slurry was added to 9.9 mL of sterile buffer. After thorough mixing, this suspension was further dilutedby successive 1/100 and 1/10 dilutions. One-tenth of a mL of this final solution was plated onto Plate Count agar.After incubation 145 colonies were present. How many colony-forming units were present in the total 10 gramsample of hamburger?

Please count the cells in grids 1, 3, 7, and 9. Calculate the cell density (a) and cell viability (b) for this sample. (assume we started with 100 microliters of cells and added 100 microliters of trypan viability blue). Hemacytometer Grid 123 5 6 789 4 Enlarged view O O O 8

Imagine you have been given a liquid culture of yeast with a starting concentration of 3.67 x 10' cells/ml and are asked to carry out the sample dilution process shown in the figure below. 100μl 100μl 100μl 100μl 100μl 0.9ml 0.9ml 0.9ml H2O H₂O 6.9ml 0.9ml H₂O H₂O H₂O Original 10-1 102 10-3 104 Culture 105 100μl 100μl 100μl Plate A Plate B Plate C a. How many colonies should have been present on Plate A in this example? - Answers must be whole numbers as partial colonies are not expected. b. Imagine you carried out the same dilution scheme shown in the figure above, but now, you do not know the concentration of the original culture. If you counted 163 colonies on Plate B, what is the concentration of cells/ml in the original culture?

The total number of cells in a culture is counted using the trypan blue exclusion assay and is found to be 6.8 x 106 cells/ml. Each well in a 6 well plate requires 2 x 105 cells. How should the solution be diluted so that 1ml can be added to each well?

Below is a diagram of the serial dilution of a culture with 1 x 10º cells. Fill out the missing information. 250 Culture Diluent 1 x 10° cells/mL 9 mL 9 mL 9.9 mL 9.9 mL 99.9 mL Volume to add to diluent Final Dilution level Theoretical count after plating 100 uL

Refer to the following diagram: 100 ul 100 uL 100 pl 100 µL 100 pl 100 pL 100 pl Volume to transfer A B C D E F G 900 uL in each tube 10 102 10 10 10 10 10 Dilutions E.CoN culture Volume of the diluted sample plated 100 ul 100 μL 100 pL 100 ul Volume of the 10 ml 10 ml original sample plated 10 ml 10 ml Plate D Plate E Plate F Plate G Given that Plate D has too many colonies to count, and Plate G has no colonies at all as a result of serial dilution, draw out all four plates and demonstrate what they might look like (assuming serial dilution has been performed correctly). Based on your drawings, identify the number of CFU/ml for Plate E and Plate F. Show your calculations.

The following is result from a standard plate count. What is the cell density of the undiluted culture? Please follow all SPC rules. (TNTC: too numerous to count)

Why are the results of plate counts expressed as the number of colony-forming units, rather than the number of cells?

ery t ess Which method of counting cells would you use for each of these situations? Viable Cell Count Optical Density measurement Direct cell count [Choose ] [Choose ] ✓ [Choose ] You are attempting to quantify the ability of cleaning agents to kill bacteria in a liquid culture You are attempting to determine the doubling time of Escherichia coli in various liquid media You are attempting to quantify the ratio of contaminating rod-shaped cells in your culture of spherical Staphylococcu