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Unit Conversions

You will often run into protocols that express DNA and protein units as concentrations, masses, and moles/molarity. It is important to be able to easily convert between these units. There are many reference books that describe how to make these conversions easily. Find the unit equivalencies and answer the questions below.

1- What is the average molecular weight of an amino acid?______________ Da

2- What is the average molecular weight of a nucleotide? ______________ Da

3- What is the average molecular weight of a base pair? ______________ Da

4- What is the molecular weight of a 100 bp dsDNA fragment? ______________ Da

5- 1 µg of dsDNA that is 1000 bp in length is equivalent to how many pg? _____________pg

6- If you have 3.03 pmol of dsDNA that is 1 kbp in length, how many µg do you have? ______________µg

7- What size of dsDNA has the following equivalency: 10 µg = 3.03 pmoles? _________________kbp

8- During ligation of dsDNA fragments to a dsDNA vector it is important to set the concentration of free DNA ends to the proper ratio. Ratios of vector to insert often range from 1:1 to 1:3. If you start with 1 µg of a 1000 bp insert, determine the number of µg of a 3000 bp vector that would be needed for a molar ratio of ends to be:

V:I

1:1 ____________________µg vector

1:3 ____________________µg vector

9- Two kbp of DNA is capable of encoding how many amino acids? _______________ aa

10- Two kbp of DNA is capable of encoding a protein of what molecular weight? _______________ kDa

11- You are preparing to set up a sequencing reaction and want to add 3.2 pmol of primers in 1 µL. The custom primer that you want to use was delivered to you as dried primer. You must resuspend it to the proper working concentration. The primer is 24 bases in length and the label on the bottle says that there is 496 ng of primer in it.

How much np water would you add to the bottle containing the primer? ___________________µL

What would be the final concentration of primer in the bottle? ____________________µM

12- If you have a 31 nucleotide primer that you want to use for sequencing that is at a concentration of 16.7 µg/mL, what volume of primer would you add to your sequencing reaction to get 3.2 pmol? __________________µL