This is an interesting question you pose, and is one that has been widely
studied over the last 50 years. The structural differences between RNA and
DNA are well understood, though there is still some debate surrounding the
dominant energetics underlying these nucleic acid interactions. This is a
complicated issue, and in the interest of brevity I抦 assuming you have
some general knowledge that I抣l skip over. To address the differences in
thermostability, we have to understand the chemical and structural
differences of DNA versus RNA then the energetic consequences of these
First, let us address the problem of helix formation; both RNA and DNA have
comparable folding mechanisms, that is the formation of base pairing
interactions with a second strand (or same-strand in the case of hairpin
formation), which (1) involves hydrogen-bond formation between opposing
strands, (2) stacking of base pairs on top of one another, (3) reducing
conformational freedom of the phosphodiester backbone.
The first component, base-pairing through hydrogen-bonding interactions may
not be an important factor in comparing DNA versus RNA. In terms of the
individual purines and pyrimidines, the only difference is found in
comparing uracil with thymine (which bears a 5� methyl group lacking in
uracil). This is known to contribute only a small fraction of the total
energy of base-pairing, adding slightly MORE energy to a DNA dA:dT base
pair compared to an RNA A:U base pair. We can ignore this as the primary
source of the high relative thermostability of RNA.
The second and third components are interlinked, since it抯 the
conformation of the phosphodiester backbone that ultimately determines the
relative orientation of one plane of paired nucleotide bases relative to
the nearest neighbor base pairs. For a given nucleotide in either a DNA or
RNA strand, there are no fewer than 6 degrees of freedom (rotatable bonds),
counting two for each phosphate-oxygen, one to the C5� carbon, one between
C5� and C4�, one between the C3� and the oxygen on the phosphate of the
next nucleotide (that抯 five), and finally rotation of the purine/pyridine
base relative to the C1� of the ribose or deoxyribose sugar. In the case
of non-base paired, single-stranded RNA or DNA, all six of these bonds are
freely rotatable which makes these polymers extremely flexible. In order
to become double-stranded, every nucleotide must adopt a single 損referred�
conformation, which requires that all six of these rotatable bonds be fixed
into a single orientation. This is a VERY unfavorable process in terms of
the energetics of forming a double-stranded DNA or RNA, but is largely the
same process for both molecules.
The only other major difference between RNA and DNA is the detailed shape
of the double-helix, A-form for RNA and predominantly B-form for DNA
(please refer to your textbooks or to any of the references below for
additional detail). RNA has never been observed to take on a B
double-helix; the presence of that 2�-OH almost exclusively locks the
ribose into a 3�-endo chair conformation, eliminating the possibility of a
stable B-helix. However, the deoxyribose sugar may alternate between
2�-endo and 3�-endo conformations, allowing DNA to switch between B-form
and A-form under the right circumstances. Note that hybrids of DNA:RNA
(one strand of each in a double-helix) adopt an A-form conformation. (To
better understand the differences in allowable sugar puckers, you might
wish to return to your organic chemistry ball-and-stick models).
The B-form of DNA (in the presence of physiological Na+ or K+) is found at
high relative humidity; large numbers of water molecules are tightly bound
(to the tune of almost 1:1 water/nucleotide). By comparison, it has been
shown that A-form RNA and A-form DNA both are dehydrated somewhat;
measurements of 75% the number of tightly bound water molecules compared to
B-form DNA are commonly cited. There is a distinct difference between
tightly bound water and bulk solvent that will have profound energetic
consequences. In fact, by putting DNA into a dehydrating medium (such as
low salt and high concentrations of ethanol), one can drive the
interconversion of B-form DNA into A-form. Curiously, high salt (>2.5 M
NaCl) and high concentrations of ethanol will drive B-form to Z-form (a
left-handed helix) for DNA, and at elevated temperatures for RNA as well.
The source of these effects are largely Coulombic (charge-charge
interactions) in nature, having to do with the unfavorable interactions
between adjacent phosphates on the backbone and the ability of solvent
composition to diminish (high salt/high humidity) or maximize (low salt/low
humidity) these unfavorable interactions, the details of which are
unapproachably complicated for our discussion.
There are important structural differences between A-form and B-form
helices that we must consider, notably in the diameter of the duplex, the
number of base pairs per turn, the tilt of paired bases relative to the
helical axis, and the solvent accessibility of major and minor grooves. Of
these factors, it is the relative orientation and overlap of
nearest-neighbor base pairing interactions that, though only subtly
different, have contribute to the observed differences in thermostability
of RNA and DNA.
I抳e touched on a few important driving forces governing the transition
between duplex and single-stranded nucleic acids, and some of the potential
STRUCTURAL differences in these interactions between RNA and DNA. In terms
of the relevant energetic contributions, the stacking of base pairs, one
above the other, plus the hydrogen bonds between bases provide the
stabilizing enthalpy of the helix, adding substantial energy stabilizing
the duplex when summed over the length of the DNA/RNA. Both cross-strand
and same-strand van der Waals interactions among bases are important; the
magnitude of these favorable interactions are slightly different for RNA
(more stable) than for DNA; these small differences become large when
summed over many base pairs. The charged phosphate groups repel one
another by Coulomb抯 law of repulsion between like charges, an
enthalpically unfavorable interaction. As mentioned above, the formation
of a double-helix results in a significant reduction in the conformational
degrees of freedom, which is entropically unfavorable in an equally big
way, and are also subtly different in A-form versus B-form.
In total, the single-strand to double-strand transition for both DNA and
RNA is enthalpically favors the helix and entropically favors
single-stranded conformation. For RNA, deltaH ~ 40 kJ mol-1/base pair and
deltaS ~ 105 J K-1 mol-1/base pair (note the entropy is a function of
temperature). For DNA, deltaH ~ 35 kJ mol-1/base pair and deltaS ~ 90 J
K-1 mol-1/base pair. These are VERY large and OPPOSITE driving forces.
In terms of the free energy, the balance of these interactions, we observed
a higher melting temperature of RNA relative to the same sequence in DNA
under normal conditions. The dominant source of this slightly higher
energy for RNA is generally attributed to modestly better base-stacking
energy in the A-form conformation. The precise nature of the molecular
driving forces remain an active area of research. Experimentally, one
observes very little difference in thermostability between RNA:DNA
double-helix compared to an all RNA double-helix, consistent with the
theory that the source of thermostability is due largely the result of
A-form versus B-form conformational differences, not strictly differences
in ribose versus deoxyribose chemistry.
Because DNA forms a double helix.
as DNA is more stable than RNA .So,RNA gets easily hydrolysed easily by hydrolysing phosphodiester bond.
RNA is shorter than DNA because it is less stable than DNA due the presence of hydroxides.
DNA is more stable form then RNA b/c DNA is present in double helix form & is highly super coiled which make it more stable and carries genetic information from parents to off springs.
DNA is more stable than RNA. DNA is double-stranded and forms a double helix. RNA is usually single-stranded and folds back on itself to form stem-loop structures. RNA has 2'-OH group that can participate in intramolecular reactions, facilitating hydrolysis.
Both DNA and RNA exist as single and double strands. yet the structure of a DNA is more stable then RNA. The main difference between the two nucliec acids is that DNA contains Deoxyribose and RNA contains ribose sugar which has a free hydroxyl group in its pentose ring which makes it prone for hydrolysis, thereby making it more unstable than the DNA.
RNA viruses are more dangerous because they mutate more rapidly than DNA viruses.
The sugar in RNA is ribose, whereas the sugar in DNA is deoxyribose. The only difference between the two is that in deoxyribose, there is an oxygen missing from the 2' carbon (there is a H there instead of an OH). This makes DNA more stable/less reactive than RNA.
Complementary DNA (cDNA) is a doublestranded DNA version of RNA . Messenger RNA is a more useful predictor of a polypeptide sequence than DNA, because the introns have been spliced out. Scientists use cDNA rather than mRNA itself because RNAs are less stable than DNA.
The reason that the instructions for creating proteins are stored as DNA, and not RNA is that RNA is much less stable than DNA. This means that if the information (or message) for how to create a protein was kept on RNA, it would soon degrade - and the instructions would be lost. DNA is much more stable than RNA, and because it does not leave the nucleus (in eukaryotic cells) it is much less likely to be degraded. This is why the instructions for protein synthesis cannot originate with RNA. DNA is more stable for many reasons, two of the simplest being; it is double-stranded (the hydrogen bonds in the centre provide stability) and it contains an H on its 2 position instead of an OH (less likely to be involved in reactions).
DNA is more stable than RNA and that is why it evolved as a long term storage of genetic information
According to Biologists, DNA is more stable than RNA and therefore has a greater ability to store genetic information within the nucleus.
Neither RNA nor DNA are dangerous; your body needs both to survive.
In what sense ??If you treat DNA with the digesting enzyme DNAse, then the DNA is gone!-I have to say DNA is very stable than RNA though.
DNA is chemically more stable and replicates with fewer errors (mutations) than RNA.
during replication RNA-polimeraze it make a lot of erros.In this ways RNA viruses it mutate faster than DNa viruses.
Scientists theorize that RNA was present before DNA was made because RNA is much more simpler than DNA and some can even act as an enzyme.
No... DNA is much longer than RNA.
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 RNA has two hydroxyl groups). These hydroxyl groups make 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.
The only difference between deoxyribose and ribose is that the Oxygen from the 2' carbon is not there in the deoxyribose - 'deoxy' meaning less oxygen. This makes DNA much more stable than RNA, as RNA is easily destabilised at basic pH.
DNA is less stable than RNA,hence it is used to carry genetic information, as during many cellular activities,like DNA replication, transcription, DNA as to unwind. DNA is found in the nucleus
DNA is named DNA because it is de-oxy ribo nucleic acid. In contrast to RNA, DNA doesnt have 2'-oxygen in the ribose sugar hence it is stable than RNA. Chemically DNA is the same for any genes that code for different proteins.
The initiation of the reaction is favoured energetically by formation of this RNA-DNA hybrid.This hybrid is more stronger than DNA-DNA hybrid