|MadSci Network: Molecular Biology|
Because you are asking a very particular question, I assume you have some background in nucleic acids.
As you said, the difference between DNA and RNA is mainly at the 2í carbon of the sugar. I will begin to answer your second question which is why the sugar of DNA doesnít have this particular oxygen. I donít recall having read anywhere the reason about this difference. I donít think that someone has found the real answer about this topic. However, the fact that RNA has a 2íOH (2íH for DNA) seems to give it a certain chemical instability resulting sometimes in a break in the phosphodiester backbone. This is very accelerated when the local pH is high. I believe that natural selection has chosen DNA to carry genetic information because of its chemical stability and of other qualities that we are not aware of yet.
About the importance of the difference, I suggest to go read the following message in the MadSci web site because it contains all the information you want and much more !
Hope this helps !
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