Question

A 3 kb double-stranded DNA plasmid is dissolved in water at 1 mg/ml. Given an average relative molecular mass per nucleotide of 300, what is the concentration of this plasmid?
a) 0.55 µM
b)   1.67 µM
c) 3.33 µM
d)   0.33 µM

This question is biochemistry question

Answer 1

The correct option is c) 3.33 µM.

Average relative molecular mass per nucleotide of 300 => 1 mol = 300 g

=> 1 g = 1/300 = 0.003333 mol = 3.333 mmol

=> 1 mg = 3.333 mol.

Solution formed is 1mg/ml = 3.333 mol /ml = 3.33 M.