The key difference between DNA and mRNA is that the DNA is one of the major types of nucleic acid which is double-stranded while mRNA is a type of ribonucleic acid which is single-stranded.
Nucleic acids are large macromolecules present in all known forms of life. There are two major types of nucleic acids as Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA). Furthermore, RNA exists in three forms. They are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). DNA, in the form of genes, contains the genetic information to code for proteins. And, these DNA sequences hand over their genetic information into mRNA by going through the first step of gene expression, which is transcription. Then, the mRNA sequence carries the genetic code to ribosomes (site of the translation) in order to produce the protein; this is the second step of gene expression. Ultimately, the genetic information of the mRNA sequence is converted into a protein using rRNA and tRNA. That completes the gene expression successfully. The main aim of this article is to discuss the difference between DNA and mRNA.
CONTENT
1. Overview and Key Difference
2. What is DNA
3. What is mRNA
4. Similarities Between DNA and mRNA
5. Side by Side Comparison – DNA vs mRNA in Tabular Form
6. Summary
What is DNA?
DNA is the basic genetic material in almost all living organisms except in some viruses. The main functions of these molecules are to store heredity information and control protein synthesis. Deoxyribonucleotides are the building blocks of DNA. These deoxyribonucleotides polymerize with each other and form polynucleotide sequences. A DNA molecule has two long polynucleotide chains coiled into a double helix structure. Hence, DNA exists as a double-stranded highly coiled helix. Each nucleotide has three components: a phosphate group, a deoxyribose sugar, and a nitrogenous base (adenine, thymine, cytosine or guanine).
Figure 01: DNA
Eukaryotes store most of their DNA inside the nucleus while prokaryotes store their DNA in the cytoplasm. In humans, DNA contains about 3 billion base pairs in a total of 46 chromosomes.
What is mRNA?
Messenger RNA (mRNA) is one of the three types of RNA present in organisms. It is a single-stranded nucleic acid composed of ribonucleotides. Similar to deoxyribonucleotide, ribonucleotide also contains a pentose sugar (ribose sugar), a phosphate group and a nitrogenous base (adenine, guanine, cytosine, and uracil). The formation of mRNA occurs inside the nucleus by the process called transcription using a DNA template. It carries the genetic information of a gene to produce a protein.
Figure 02: mRNA
The main function of mRNA is to direct the synthesis of proteins by carrying the coding information from a DNA template to the site of protein synthesis: the ribosome. mRNA has a short life in comparison to the other two types of RNA.
What are the Similarities Between DNA and mRNA?
- DNA and mRNA are two types of nucleic acids.
- Their building blocks are nucleotides.
- Also, both are macromolecules having long chains.
- Besides, both carry genetic information of an organism.
- Furthermore, they both play a role in protein synthesis.
What is the Difference Between DNA and mRNA?
DNA is a type of nucleic acids which is double-stranded while mRNA is a type of ribonucleic acid which is single-stranded. So, this is the key difference between DNA and mRNA. Furthermore, a significant difference between DNA and mRNA is that the building block of DNA is deoxyribonucleotide while the building block of mRNA is ribonucleotide. Additionally, DNA contains deoxyribose sugar while mRNA contains ribose sugar. Also, DNA contains thymine while mRNA contains uracil. Therefore, we can consider this too also as a difference between DNA and mRNA.
Moreover, a further difference between DNA and mRNA is that the DNA formation occurs via DNA replication while mRNA formation occurs via DNA transcription. Besides these differences, when comparing the life span of DNA and mRNA, DNA has a long life span while mRNA has a short life span.
The below info-graphic represent more comparison regarding the difference between DNA and mRNA.
Summary – DNA vs mRNA
DNA is the genetic material of most living organisms except some viruses. It is a double-stranded nucleic acid composed of deoxyribonucleotides. On the other hand, mRNA is a subtype of RNA which is single-stranded. mRNA sequences carry the genetic codes to produce proteins from genes to ribosomes in the cytoplasm. Structurally, DNA is made up of deoxyribonucleotides containing deoxyribose sugar while mRNA is made up of ribonucleotides containing ribose sugar. Not only that, DNA contains thymine as one of the four types of nitrogenous bases while mRNA has uracil as a nitrogenous base instead of thymine. Since DNA is double stranded, it is more prone to damage by UV compared to mRNA. Thus, this summarizes the difference between DNA and mRNA.
Reference:
1. “What Is DNA? – Genetics Home Reference – NIH.” U.S. National Library of Medicine, National Institutes of Health, Available here.
2. Britannica, The Editors of Encyclopaedia. “Messenger RNA.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 18 Feb. 2019, Available here.
Image Courtesy:
1. “DNA Structure+Key+Labelled.pn NoBB” By Zephyris – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “MRNA” By Kelvinsong – Own work (CC BY 3.0) via Commons Wikimedia