DNA calculation questions for practise
1. If a sample containing pure double stranded DNA has an absorbance of 1 at 260nm,
then it contains approximately 50ug/ml of double stranded DNA. How much DNA is in
a sample with a 260nm reading of 0.6?
1b How much DNA is in the original sample when the diluted sample (diluted 1/124)
gives a reading of 0.2 at 260nm?
2. OD 260 of you diluted DNA solution is 0.3. OD 280 is 0.15. The DNA was diluted
1/1000 before reading in the spec. What is its concentration?
3. OD 260nm=0.3, OD 280nm=0.6, what is the concentration of your DNA and is it
pure?
4. You isolate DNA from bacteria and do a 11ul/9.68 ml dilution followed by a second
dilution of 1/100. You read the 1/100 dilution in the spec and get OD 260nm=0.21
and OD 280nm= 0.08, what is the concentration of your DNA and is it pure?
5. You isolate DNA from human cells and take 17ul and add it to 0.3ml and then take
0.15ml and make it up to 860ul. You read this solution in a spec at 26onm and get 0.
45, at 280nm you get 0.19, what is the concentration of your DNA and is it pure?
6. You isolate DNA from a virus with a single stranded DNA genome. You take 250ul
and make it up to 1097ul . The OD 260 is 0.6. What is the concentration of DNA.
7. You isolate RNA from a virus with a single stranded RNA genome. You take 150ul
and make it up to 1.45ml . The OD 260 is 0.45. What is the concentration of RNA
8. You isolate a pellet of DNA and resuspend in 660ul to make your stock solution. You
take 0.03ml of this and add it to 330ul. You then take 20ul of this dilution and add it to
768ul. You read the OD 260 of the most dilute sample and find it to be 0.43. What is
the concentration of DNA in your stock and how much DNA do you have in total.