mRNA vs tRNA
DNA and RNA are macromolecules which are polymers of nucleotides. Deoxyribonucleic Acid or DNA is responsible for carrying genetic information from generation to generation while Ribonucleic Acid or RNA mainly involve in protein synthesis. Although DNA is the main genetic material for most living organisms, RNA is the genetic material of some viruses. RNA composed of pentose carbon sugar and nitrogenous bases. These bases are again categorized as purines and pyrimidines. The purines bases are Adenine (A) and Guanine (G) and pyrimidines are Cytosine (C) and Uracil (U). RNA is located normally within the cytoplasm. There are three classes of RNA: mRNA, tRNA and rRNA are these three classes which are involved in protein synthesis using information of DNA.
Messenger RNA or mRNA contains ribonucleotides which involve in protein synthesis. They encode the amino acid sequence of proteins which is called translation. In the translation mRNA is read as the triplet codons. The genetic code of DNA specifies the amino acid correspondent to each of the triplet codons. Molecules of mRNA are transcribed from DNA very similar to the DNA replication, but only one DNA template is transcribed. The base of Thiamin (T) is substituted with U. In eukaryotes, a single mRNA is coded for a single polypeptide chain while, in prokaryotes, several polypeptide chains may be coded from a single mRNA strand.
Most mRNA molecules have a short life span and high turnover rate. So they can be synthesized over and over again from the same stretch of template DNA. In this short life time, it is processed, edited and transported before the translation in eukaryotes. During the processing, several things occur such as 5′ cap addition, splicing, editing, and polyadenylation. In prokaryotes processing does not occur. In eukaryotes, translation and transcription occur in different places, so they need to be transported extensively.
The main function of transfer RNA or tRNA is to carry amino acids to the ribosomes and interact with the mRNA in translation of protein synthesis. These tRNAs have 70-90 nucleotides. All matured tRNA molecules have secondary structure containing several hairpin loops. At the end, the tRNA has anticodon which binds with mRNA. These amino acids are joined in the way specified by the mRNA. There is at least one type of tRNA for each amino acid. Because of that, in a cell tRNA is produced largely. These tRNAs are synthesized in a precursor both in eukaryotic and prokaryotic cells. This tRNA processing involves removal of short leader sequence from 5′end, addition of CCA instead of two nucleotides at 3′end, chemical modification of certain bases and excision of an intron.
What is the difference between mRNA and tRNA?
• Transfer RNA or tRNA carries amino acids to the ribosomes and interacts with the mRNA in translation of protein synthesis, and mRNA sequence is transcribed from DNA template similar as DNA replication and encode for amino acid sequence of proteins.
• The structure of mRNA is unfolded linear molecule whereas tRNA molecule is a 3-D structure containing several hairpin loops.
• At one end of the tRNA, it has CCA trinucleotides which are common to all tRNA molecules but mRNA lacks such characteristic.
• In a cell, tRNA is produced largely due to existing of at least one type of tRNA for each amino acid. So, comparing to the amount of tRNA, amount of mRNA is lower.
• In the translation mRNA is read as codons whereas tRNA does not.
• Transfer RNA has an anticodon, but mRNA does not have.