The two major kinds of RNA (Ribonucleic Acid) found in cells are rRNA and mRNA. RNA is mainly a single-stranded molecule with the bases adenine, guanine, cytosine, and uracil. In all RNA nucleotides, the pentose sugar is ribose. Transcription, with the help of the RNA polymerase enzyme, produces RNA. Even though every RNA type has a distinct purpose, both RNA types are primarily involved in protein synthesis.
rRNA vs mRNA
The main difference between rRNA and mRNA is that mRNA carries the amino acid sequence of a protein’s coding instructions, whereas rRNA is coupled with proteins to construct ribosomes. The rRNA molecule has a sphere form, whereas the mRNA molecule has a linear structure. The rRNA lacks codon or anticodon sequences, whereas Codons are found in mRNA.
The fundamental factor of ribosomes is ribosomal RNA, or rRNA. These are protein synthesis factories. The 60S and 40S subunits of eukaryotic ribosomes are made up of two nucleoprotein complexes. The 60s RNA subunit is separated into 28S RNA, 5S RNA, and 5.8S RNA, whereas the 40S RNA subunit is 18S RNA.
Messenger RNA (mRNA) is synthesized as heterogeneous nuclear RNA in the nucleus of eukaryotes (hnRNA). In addition, hnRNA processing produces mRNA. This (mRNA) will now reach the cytoplasm and participate in the production of proteins. The half-life of mRNA is short, yet its molecular weight is high. The relationship between gene and protein is referred to as this.
Comparison Table Between rRNA and mRNA
| Parameters of Comparison | rRNA | mRNA |
| Definition | The ribosomes are formed using rRNA, also known as ribosomal RNA. | mRNA, or messenger RNA, is the link between a gene and a protein, and it is produced by RNA polymerase after the gene has been transcribed. |
| Role | The structural underpinning for the creation of ribosomes is provided by rRNA. | mRNA transports genetic material from the nucleus to the ribosomes, which are responsible for protein synthesis. |
| Synthesized in | Ribosome | Nucleus |
| Size | The size of an rRNA molecule can range between 30S, 40S, 50S, and 60S. | Molecules in mammals range in size from 400 to 12,000 nucleotides. |
| Shape | The shape of rRNA is a sphere basically a complex structure. | The shape of mRNA is linear. |
What is rRNA?
The fundamental factor of ribosomes is ribosomal RNA, or rRNA. The ribosomes include rRNAs, which constitute 80 percent of the total RNA in the cell. Ribosomes are made up of two subunits, the 50S and the 30S, most of which are mainly composed of their own rRNA molecules. Small rRNAs and large rRNAs, which correspond to the large and small subunits of the ribosome, are two types of rRNAs found in ribosomes.
In the cytoplasm, rRNAs join with proteins and enzymes to produce ribosomes, which serve as the site of protein synthesis. During translation, these complex structures migrate along the mRNA molecule and aid in the synthesis of amino acids to produce a polypeptide chain. They interact with tRNAs and other proteins-synthesis-related molecules.
Correspondingly, small and big rRNAs in bacteria have roughly 1500 and 3000 nucleotides, whereas they have about 1800 and 5000 nucleotides in humans. Ribosomes, on the other hand, are substantially consistent in function and structure throughout all species. Codons or anticodons are absent in rRNA. The large ribosomal subunit (LSU) and short ribosomal subunit (SSU) are two ribosomal subunits that arrange ribosomal RNA (SSU). The rRNA types employed to create the subunits vary between certain subunits. When tRNA is sandwiched between the SSU and the LSU, rRNA starts the catalysis of protein synthesis.
What is mRNA?
mRNA, or messenger RNA, is the result of an RNA polymerase-transcribed gene and serves as a link between the gene and the protein. The amount of mRNA in a cell is only 5% of the total RNA. In terms of nucleotide sequence and structure, mRNA is the most diverse form of RNA. It contains complementary genetic code in the form of codons, which are triplets of nucleotides copied from DNA during transcription.
Each codon codes for a specific amino acid, albeit the same amino acid, might be coded for by many codons. Only 20 of the 64 potential codons or triplet bases in the genetic code correspond to amino acids. There are also three stop codons, which signify that ribosomes must quit translating proteins.
In eukaryotes, the 5′ end of mRNA is capped with a guanosine triphosphate nucleotide as part of post-transcriptional processing, which aids in mRNA identification throughout translation or protein synthesis. Likewise, several adenylate residues are appended to the 3′ end of an mRNA to slow enzymatic destruction. An mRNA’s 5′ and 3′ ends both contribute to its stability to the mRNA.
In addition, mRNA molecules have changed bases in their inner structure, such as 6- methyladenylates; these mRNA molecules also have an intron, which would be spliced out before the full mRNA molecule is formed.
Main Differences Between rRNA and mRNA
- rRNA, or ribosomal RNA, is utilized to form ribosomes, whereas mRNA, or messenger RNA, is the link between gene and protein that is created by RNA polymerase from the transcribed gene.
- rRNA forms the structural basis for ribosome production, whereas, on the other hand, mRNA transports genetic data from the nucleus to the ribosomes for protein synthesis.
- rRNA is synthesized in the ribosome, however, mRNA is synthesized in the nucleus.
- The rRNA molecule has a sphere shape (complex structure), whereas the mRNA molecule has a linear form.
- Anticodon and codon sequences are absent from rRNA, whereas codons are present in mRNA.
Conclusion
Ribosomal RNA (rRNA) is a type of large RNA that helps ribosomes and ribosomal proteins develop. The ribosome is a protein-synthesizing organelle in the cell that converts an mRNA molecule’s coding sequence into a polypeptide chain. The nucleolus is where rRNA is synthesized. Small rRNA and big rRNA are the two kinds of rRNA molecules produced whereas, From the nucleus to the ribosomes, messenger RNA (mRNA) molecules transport a transcript of a gene that encodes for a specific functional protein. Transcription is the process through which mRNA is produced. RNA polymerase is the in-charge of transcription. In conclusion, The ribosome contains the rRNA molecule, which functions as the translation organelle, whereas An mRNA molecule is a form of RNA that transports a piece of the DNA code to other areas of the cell to be processed.
References
- https://www.sciencedirect.com/science/article/pii/S1097276509002706
- https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/j.1462-2920.2010.02415.x