Question

You dilute an original sample 1:30. You then count the number of yeast in the 1:30 dilution. You count an average of 7 cells in the 1/25 mm2 sized boxes. What is the concentration, in cells/ml, of the original sample?

Answer 1

Answer:

The concentration, in cells/ml, of the original sample is 52500 cells/ml

Explanation:

Given

- Average number of cells in 1/25 mm^2 sized box (considering 1 box) is 7

- The depth of each box of a hemocytometer is 0.1 mm

To find the Volume:

Volume = 1/25 mm^2 * 0.1 mm^3 = 0.004 mm^3

Concentration of cells in this volume

[Cells in the estimated volume] = 7/0.004 mm^3 = 1750 cells/mm^3.

Knowing 1 mm^3 = 1 ml,

cell count = 1750 cells/ml.

Using the dilution factor 1:30 to correct the calculation

Final cell count after correction =  1750* 30 = 52500 cells/ml