Difference Between DNA and RNA structure

DNA vs RNA structure

Nucleic acids are the building blocks of genetic material of all organisms. The nucleic acids are of two types depending on the sugar molecule in their structure. Nucleic acids are long chains of nucleotides joined by phosphoric acid bonds. These nucleotides inturn are made of pentose sugar and a purine/ pyrimidine structure.


Deosyribonucleic acid (DNA) is the genetic material in all eukaryotes and some prokaryotes. It is a nucleotide chain composed of purines/pyrimidines bound to a pentose sugar (Deoxyribose). DNA is made of nucleotides Adenine, Thymine, Cytosine and Guanne.

DNA is essentially doublestranded with two nucleotide strands bound by hydrogen bonding between the bases. Adenine (A) pairs with Thymine (T) whereas Cytosine (C) pairs with Guanine (G). Hence the amount of A is always equal to T and C is equal to G. Phosphate and sugar moieties are found on the outside of the helix where as the bases remain in the interior of the helix. These strands run in opposite directions. The double helix is further coiled around histones and highly compressed and remain as chromosomes in eukaryotes.


RNA stands for riboxynucleic acid. RNA is not an integral part of the chromosomes. They are derived from DNA for production of proteins. This is hence an information transfer molecule. The mRNA derived from DNA is transported to the cytoplasm where is undergo further translation mechanism to produce protein.

RNA for the most part exists as single strand, but it can form several structural features due to the complementary base pairing within the single strand.


Structurally RNA is different from DNA in consisting of ribose as pentose sugar and Uracil as the pyrimidine group. RNA is not double helix as DNA, but it forms similar helical structures by being wound back due to base pairing. Just as in DNA, the bases are hydrogen bonded in RNA in these helical regions. RNA exists as single helix in most regions.

The pentose sugar in RNA is ribose and in DNA it is deoxyribose. Deoxyribse has one oxygen atom less on the 5’ Carbon of the ribose sugar.

Since RNA has few or no base pairs the Chargaff rule of equivalence of Adenine with Thymine and Cytosine with Guanine cannot be extended to DNA. In RNA, Thymine is replaced by Uracil which binds with Adenine to form helical structures which are found occasionally

Structurally, the DNA is a more compact molecule having specific height, width, and dimensions of major and minor grooves.

Functionally DNA acts as the genetic material which is passed on to the generations. RNA act as the information carrier mechanism through which the body produces fully functional proteins.


Even though they are structurally and functionally diverse, both molecules are essential in protein synthesis. DNA acts as the precursor molecule of transcription where as RNA forms the base of translation process.