The key difference between DNA and RNA structure is that the DNA structure is a double helix composed of two complementary strands while RNA structure is single-stranded.
Nucleic acids are macromolecules or biopolymers. Moreover, they are the building blocks of genetic material of an organism. They are comprised of nucleotide chains linked via phosphodiester bonds between 5′ phosphate group of one nucleotide and the 3′-OH group of the adjacent nucleotide. Accordingly, there are two types of nucleic acids namely deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) which are vital compounds in living organisms. A nucleotide is the basic unit of the nucleic acids. Accordingly, the deoxyribonucleotide is the building block of DNA while the ribonucleotide is the building block of RNA. Structurally, there are three components in a nucleotide. They are a pentose sugar, phosphate group and a nitrogenous base. These components differ between two major types of nucleic acids. DNA contains deoxyribose sugar whereas RNA contains ribose sugar.
CONTENTS
1. Overview and Key Difference
2. What is DNA Structure
3. What is RNA Structure
4. Similarities Between DNA and RNA Structure
5. Side by Side Comparison – DNA vs RNA Structure in Tabular Form
6. Summary
What is DNA Structure?
Deoxyribonucleic acid is the genetic material of all eukaryotes and some prokaryotes. Hence, it contains the genetic information that requires for the overall functioning of an organism. Structurally, DNA is a polymer of deoxyribonucleotide monomers. Deoxyribonucleotide has three components; deoxyribose sugar, a nitrogenous base (adenine, guanine, cytosine and thymine) and a phosphate group.
Figure 01: DNA Structure
Furthermore, DNA molecules exist as double-stranded helix made from two complementary DNA strands, unlike RNA. Hydrogen bonds link these two strands. Here, the hydrogen bonds occur between nitrogenous bases. Adenine links with thymine by two hydrogen bonds while cytosine binds with guanine by three hydrogen bonds. In the DNA helix, phosphate and sugar moieties are situated on the outside of the helix whereas the bases remain in the interior of the helix. Also, the two strands of DNA run in opposite directions. Furthermore, DNA molecules tightly coil with histone proteins and make a thread like structures called chromosomes in eukaryotes.
What is RNA Structure?
Ribonucleic acid or RNA is the second type of nucleic acid present in many living organisms. RNA is not an integral part of the chromosomes. They are derived from the DNA during the transcription of genes to produce proteins. The genetic information hidden in the DNA molecule converts into a mRNA molecule through transcription. Hence, it is an information transfer molecule.
Figure 02: RNA Structure
Once the transcription completes, mRNA molecule leaves the nucleus and travels into the cytoplasm for translation. At the end of this process, it yields a protein. Furthermore, RNA, for the most part, exists as a single strand, but it can form several structural features due to the complementary base pairing within the single strand.
Besides, the RNA composes ribonucleotides, which are monomers of RNA. Ribonucleotides consist of the ribose sugar, a phosphate group and a nitrogenous base. Four nitrogenous bases present in RNA are adenine, uracil, cytosine and guanine.
What are the Similarities Between DNA and RNA Structure?
- DNA and RNA are nucleic acids.
- Both are polymers made from nucleotides.
- Also, both their nucleotides have a similar structure with slight differences.
- Moreover, the nucleotides of each nucleic acid have two different purine bases and pyrimidine bases.
- Furthermore, they both contain a pentose sugar and a phosphate group.
What is the Difference Between DNA and RNA Structure?
DNA and RNA are two types of nucleic acids present in living organisms. DNA is present in the nucleus of eukaryotes while RNA is present in the cytoplasm. A major difference between DNA and RNA structure is in their monomers. Deoxyribonucleotide is the basic unit of DNA while ribonucleotide is the basic unit of RNA. Furthermore, DNA contains thymine while RNA contains uracil instead of thymine. Another difference between DNA and RNA structure is that DNA exists as a double-stranded molecule while RNA exists as a single-stranded molecule.
The below infographic provides more details on the difference between DNA and RNA structure.
Summary – DNA vs RNA Structure
Even though they are structurally and functionally diverse, both molecules are essential in protein synthesis. DNA acts as the precursor molecule of transcription whereas RNA forms the base of the translation process. Nucleotides differ in two types of nucleic acids. Deoxyribonucleotides are the monomers of DNA while ribonucleotides are the monomers of RNA. Furthermore, uracil is present in RNA while thymine is present in DNA. The key difference between DNA and RNA structure is that the DNA exists as a double-stranded helix while the RNA is a single-stranded molecule.
Reference:
1.“DNA.” Wikipedia, Wikimedia Foundation, 6 Oct. 2018. Available here
2.Nature News, Nature Publishing Group. Available here
Image Courtesy:
1.”DNA Structure+Key+Labelled.pn NoBB”By Zephyris – Own work, (CC BY-SA 3.0) via Commons Wikimedia
2.”Difference DNA RNA-EN”By Roland1952, (CC BY-SA 3.0) via Commons Wikimedia