Structure and Functions of Different Types of RNA

The chemical ribonucleic acid (RNA) can be found in the genomes of nearly all living things, including viruses. In the nucleic acid, ribose and nitrogenous bases and phosphate groups make up the nucleotides. There are four nitrogenous bases: cytosine, adenine, guanine, and uracil. The majority of RNA is single-stranded, although there are certain rare double-stranded RNA viruses. The length and structure of the RNA molecule can be varied. Many human diseases can be caused by RNA viruses, which employ RNA instead of DNA as their genetic material. Protein synthesis begins with transcription and ends with translation, both of which take place in the cell. Eukaryotes and prokaryotes have different RNA synthesis methods and roles. Gene expression is regulated by specific RNA molecules, which may one day be used therapeutically to treat human ailments.

Definition of RNA

The polymeric molecule ribonucleic acid (RNA) is critical to the coding, decoding, control, and expression of genes in many different biological processes. DNA and RNA are both types of nucleic acids. Nucleic acids are one of four primary macromolecules required by all known living forms, along with lipids, proteins, and carbohydrates. A chain of nucleotides, like DNA, except RNA is found in nature folded over itself rather than paired double-stranded nucleotides like DNA. Genes are carried by messenger RNA (mRNA) in cells and direct protein synthesis by employing the nitrogenous bases guanine, uracil, adenine, and cytosine (GUAAC), respectively. RNA genomes are used by several viruses to encode genetic information.

In some cells, RNA molecules perform an active role by catalysing biochemical events, directing gene expression, or monitoring and transmitting responses to cellular signals. This is one of the many processes in which RNA molecules guide the synthesis of proteins on ribosomes, a ubiquitous function. As amino acids are transported to and processed by an enzyme based on the ribosome’s ribosomal RNA, coded proteins are formed.

Structure and Function of RNA

RNA structure

RNA is usually made of a single strand of ribonucleotides held together by phosphodiester bonds. In the RNA chain, a ribonucleotide is made up of ribose, which is a pentose sugar, one of the four nitrogenous bases (A, U, G, or C), and a phosphate group. The slight structural difference between the sugars gives DNA more stability, which makes it better for storing genetic information. RNA on the other hand, is better for its more short-term functions because it is less stable. The pyrimidine uracil is used in RNA instead of thymine, which is used in DNA. It forms a base pair with adenine that is the same as thymine. Even though RNA only has one strand, most types of RNA molecules have a lot of intramolecular base pairing between complementary sequences within the RNA strand. This gives them a predictable three-dimensional structure that is important for their function.

Function of RNA in Protein synthesis

Translation is the principal means by which RNA generates proteins. In order for cells to function, ribosomes must translate genetic information into a variety of proteins. Each of these three forms of RNA is crucial to the production of proteins. Viral genomes are largely constructed from RNA. Genome regulation and RNA interference are also among the other activities that RNA editing can perform. This category of small regulatory RNAs, which includes microRNA, small interfering RNA, and small nuclear RNA, is responsible for carrying out these functions.

The initiation, elongation, and termination phases are all part of the RNA translation machinery. A ribosome and tRNA join an mRNA during initiation. Methionine is encoded by the AUG codon, which is always the first amino acid in a peptide sequence. This is the first step in a long process that involves reading codons and binding amino acid-specific transfer RNAs, or tRNAs, from mRNA in a 5′-3′ direction. Once a stop codon is reached, the amino acid sequence comes to an end. Stop codons are UAG, UA, and UGA. An active protein then emerges, having been freed from the ribosomal complex. Transcription follows transcription in eukaryotic cells, although transcription and translation occur concurrently in prokaryotic cells.

Different Types of RNA 

RNA comes in many forms, but the following are the most well-known and extensively researched in the human body:

tRNA (Transfer RNA)

It is the job of the transfer RNA to aid in the ribosome’s selection of the correct protein or amino acids for the body. It is found at the amino acid’s termini. To put it simply, it serves as an intermediary between the messenger and amino acids, which is why it is named “soluble RNA”.

rRNA (Ribosomal RNA)

It is in the cell’s cytoplasm, near the ribosomes, where rRNA, or ribosomal RNA, can be discovered as part of the ribosome. The synthesis and translation of mRNA into proteins depend on ribosomal RNA in all live cells. Cellular RNA makes up the majority of rRNA, making it the most prevalent RNA in all living cells.

mRNA (Messenger RNA)

It’s called mRNA, or messenger RNA, and it’s responsible for carrying genetic material into the ribosomes and passing on instructions regarding the type of proteins that are needed by the body cells. These RNAs are referred to as messenger RNAs because of their roles in the body. When it comes to transcription and protein production, the messenger RNA (mRNA) is critical.

Conclusion

Protein synthesis is facilitated by RNA, a molecule of large molecular weight that serves as a replacement for DNA (deoxyribonucleic acid) in some viruses. For example, the nucleotides in the RNA molecule are connected to each other by phosphodiester bonds, which create different length strands. RNA contains the nitrogenous bases adenine, guanine, cytosine and uracil, the latter of which is used in place of DNA’s thymine.

RNA’s ribose sugar is a cyclical structure made up of five carbons and one oxygen atom each time. There are two carbons in the second carbon of ribose sugar that are chemically reactive, making RNA vulnerable to hydrolysis. RNA’s chemical lability compared to DNA, which does not have a reactive OH group at the same place on the sugar moiety (deoxyribose), is suggested to be one reason why DNA evolved to be the favoured transport of genetic information in most animals. In 1965, R.W. Holley defined the RNA molecule’s structure.