Examine the list below. State which organic solvents will denature DNA effectively??

Question

a) ethanol,propanol
b)urea,dimethyl ether
c)dimethyl ether,diethyle ether
*circle the correct answer

Answer 1

Ethanol and isopropanol are used in the purification of DNA. DNA precipitates but doesn't denature in such solutions (e.g. look at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=793613&dopt=Abstract for a ethanol-methyl alcohol solvent)

i've never heard of ethers used in denaturing DNA. They are not polar enough and would probably keep the DNA intact (but also probably DNA wouldn't dissolve in them)

Urea is commonly used in denaturing electrophoresis of DNA. Though urea is not a solvent itself, but it is a compound added in the aqueous buffers. Other denaturing compounds commonly used are DMSO and formamide.

The most suitable answer appears to be (b) because of urea, although dimethyl ether should have no effect. Are you sure it was not dimethyl sulphoxide (DMSO)?

Answer 2

a) ethanol, propanol. They are both fairly polar solvents that would be able to open up the double helix effectively.

Ethers are relatively non-polar and would have problems with the highly charged backbone of DNA. You should verify with others to see if I'm right.

Answer 3

A kong! humorous, i have merely reported that to some different person... you position the peanut butter contained in the Kong, and it is going to save your canine occupied for hours attempting to get all of it out - a lot less mess all round, and the manage lasts longer!

Answer 4

i'm glad you told us t ocircle the right answer