You are performing an enzymatic reaction to digest DNA and n

You are performing an enzymatic reaction to digest DNA and nothing works for you. You need find out why. You added the enzyme and the DNA the reaction yourself and you are sure you did it right. It must be the digestion buffer. The solution the digestion buffer should contain 400 mM Tris, pH 8.0 and 125 mM MgCl_2. First, you ask your colleague how he made the digestion buffer and he says: \"I mixed 0.2 ml of 2M Tris, pH 8.0 stock solution 0.25 ml of 5M MgCI_2 stock solution and I completed the solution with o 55 ml water to make a final volume of 1ml.\" Before checking your colleague\'s calculation, what important question do you have to ask first for this specific solution? (not a generic question about all solutions) You are satisfied with his answer to and you believe he made a dilution error. You use the and equation that applies to dilutions to check his calculations. Aha! you find the problem. What is it how did you find out? Note: you can either check the math or you can do the calculations yourself.

Solution

a. i must ask him he is very sure about the dilution he made and confirm that his statement is right 100%?

b. so as he said 0.2 ml of 2M tris he diluted upto 1 ml

so according to N1V1=N2V2

0.2x2x10³=1x N2 (must be 400 as need in working solution)

here N2=400

for mgCl2

0.25x5x10³=1xN2 (must be 125)

N2=1.25x10³=1250mM ok so here he made 1o times less diluted

he must have added 0.025 of 5M mgcl2 upto 1 ml