Question

22.2 pts) You are making a 50 enzyme re k tal that includes MgCla. The recipe Includes adding 4 u of a 25 mM MOC stock solution What is the final concentration of cocktail? (Show your work) that includes MgCla. The recipe for the cocktail in the reaction You perform the following serial dilution of a stock Eco broth culture that has 5.6 x 10 cells/ml 23. (1.5 pts) How many cells/ml are there in Tube A? 24.(1.5 pts) How many cells/ml are there in tube B? 25. (1.5 pts) How many cells/ml are there in tube C?

Answer 1

Answer 22)

The recipe for the cock tail includes 25 mM MgCl2 in 4 microlitre

Now in 1 microlitre, the concentration of MgCl2 is 25/4= 6.25 mM

Now 50 microlitre of cocktail includes 6.25×50= 312.5 mM

Answer 23)

The stock solution contains 5.6×10^8 cells/ ml

Dilution Is defined as the ratio of volume taken from stock to the sum of voume taken and diluent solution.

Now the dilution on tube 1 is 0.1/(0.1+9.9) = 0.1/10= 1/100

It means there is found 100 fold of reduction in cells in tube A.  

That's why the concentration of cell in tube A is 5.6×10^8/100 =5.6×10^6 cells/ ml

Answer 24)

Dilution in tube B is 1/(9+1) =1/10

That's why cell concentration in tube B is 5.6×10^6/10

=5.6×10^5 cells/ml

Answer 25)

Dilution in tube C is 1/(9+1) = 1/10

That's why the cell concentration in tube C is 5.6×10^5/10

= 5.6×10^4 cells/ml