A scientist wishes to create bacterial colonies on an agar plate for observation of growth. Unfortunately, directly adding bacteria from the original culture results in too many bacterial colonies to count. In order to create a solution of proper bacterial concentration for observation, the scientist performs a three-step 1:100 serial dilution of the original bacterial culture. What is the dilution factor of the final solution

10⁶

Explanation:

A 1:100 serial dilution is a dilution in which the concentration decreases 100 fold (i.e., in each dilution the concentration of the culture must be multiplied by 10⁻²). The question above indicates that a three-step 1:100 dilution was applied, which means >> 10⁻² x 10⁻² x 10⁻² = 10⁻⁶. Moreover, the dilution factor can be calculated by dividing the volume of the diluted solution by the volume of the concentrated solution. The dilution factor is the inverse of dilution, thereby in this case this value is equal to 10⁶ (dilution = 10⁻⁶ >> dilution factor = 10⁶).