1) If you suspect your culture of bacteria has 125 x 106 cellsper mL, what would you want the final dilution to be in order toend up with 50 cfu on a plate?
2) A 0.1 dilution is performed on a culture of bacteria in orderto perform viable plate counts. From the dilution,*0.1 mL* ofsolution is plated on solid media, and 154 colony forming unitsgrow on the plate. How many bacteria are in a single mL of theoriginal culture?
3) How many microliters of original sample arerequired to produce a final dilution of 10-3 in a totalvolume of 5 mL? 1 microliter is 10-6 L or10-3 mL.
4) There are so many microbes in a single mL of culture, it isvery difficult to perform one dilution to produce countable cells.Microbiologists need to perform a dilution series, where multipledilutions are performed in sequence to arrive at the correctdilution.
Dilutions are cumulative. Multiply the series of dilutionstogether to find the final dilution value.
If 6 serial dilutions are performed, each with a dilution of0.01, what is the cumulative dilution?
