Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.
11 posts • Page 1 of 1
I found somewhere the conclusion that: it is thought that life arose as RNA, because it is more reactive. How come? Can somebody explain me why RNA is more reactive? What this molecule has inside its structure that is said to be more reactive than DNA? All the best!
Take this question logically. As mmiaosmiling points out, the only difference between DNA and RNA, as the name implies, is the 2' hydroxyl group. This hydroxyl group makes RNA less stable than DNA because it is more prone to hydrolysis.
To expand on that, consider that in a DNA backbone, there are no free hydroxyl groups (the 3' and 5' hydroxyl groups link the 2-deoxyriboses together via a phosphodiester bond and the the 1' has been removed to attach the sugar to the nucleoside). In a RNA chain, each ribose has a free 2' hydroxyl group that is a nucleophilic center.
The consequence of this on stability is drastic, the oxygen can attack both intramolecularly (as exemplified in splicing) or intermolecularly (which may be part of the reason that it is difficult to form dsRNA longer than x00 n.t.)
In response to the initially proposed question, I have heard that some RNA can self-reporduce, which is a very interesting phenomenon when one is addressing the origin of life. It may be worth inquiring into.
Unlike DNA, RNA is almost always a single-stranded molecule and has a much shorter chain of nucleotides. RNA contains ribose, rather than the deoxyribose found in DNA (there is a hydroxyl group attached to the pentose ring in the 2' position whereas DNA has a hydrogen atom rather than a hydroxyl group). This hydroxyl group makes RNA less stable than DNA because it is more prone to hydrolysis. Several types of RNA (tRNA, rRNA) contain a great deal of secondary structure, which help promote stability.
RNA has a replicase activity, that was found in some lower organism. Also, it has got self splicing ability. it can give rise to DNA using reverse transcriptase and also the polymorphic forms of RNA that are required for protein synthesis. These abilities make it a powerful molecule. it may be very much possible that it gave rise to life.
so, first we have RNA based organism, then evolved to DNA??
11 posts • Page 1 of 1
Who is online
Users browsing this forum: No registered users and 2 guests