WHY RNA IS MORE REACTIVE?

[HELISA]

Hi,
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!

[Poison]

DNA is double strand. Make bonds. But RNA is single strand.

[HELISA]

Is this the only reason?
I found the information that RNA reactivity is somehow connected with its Hydroxyl group at 2′ position, but how this group affect reactivity of RNA, I have no clue…

[Poison]

I don’t know either. Maybe some other members can help us.

[kiekyon]

perhaps it is because the dna is longer and more complex…

[mmiaosmiling]

RNA is single strand and it has 2 -OH(hydroxy) in 2′ position and 3′ position but DNA has only 1 in 3′

[dae]

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.

[kiekyon]

from wikipedia,

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.

[kiekyon]

quote dae:

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.

how so??

[angel]

quote kiekyon:

quote dae:

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.

how so??

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.

[kiekyon]

quote angel:

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??

[Author]

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