Molecular Biology

Function of Rnas

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RNA has a wide variety of functions within each and every cell. Known fully as Ribonucleic acid, RNA functions differently than DNA. While DNA is primarily the storage material for genetic information, RNA is a carrier of genetic information, a catalyst for biochemical reactions, an adapter molecule and a structural molecule.

There are five major types of RNA that include, mRNA (messenger RNA), tRNA (transfer RNA), rRna (Ribosomal RNA), hnRNA (heterogeneous nuclear RNA) and the smaller nuclear RNAs of which there are quite a few that also have a variety of functions. Each of these types of RNA has a different function within the cell.

The main function of RNA is the translation of DNA into a protein. The first step in this process is an enzyme reaction that transcribes DNA into hnRNA, which forms a direct copy of DNA. From the hnRNA a process called capping occurs which removes introns and adds adenines and ends with mRNA as the product. The function of mRNA is to carry genetic material that will become proteins. The mRNA is then transported into the cytoplasm of the cell and out of the cell nucleus. This is how this type of RNA functions as a messenger carrying information from the DNA to the ribosome, which is the protein synthesizing organelle.

This mRNA then attaches to the ribosome and the tRNA then comes into action. The tRNA functions because it is an adapter molecule that recognizes the codons in mRNA and can covalently bond to the correct amino acid. Both the tRNA and the mRNA are necessary in this step for the production of proteins. Another type of RNA also plays a huge role in this action and that is rRNA. This type of RNA has two main functions, it provides shape and structure for the ribosome and it also helps to speed up the interactions between tRNA and the protein synthesis machinery.

In addition to these major types of RNA there are several smaller RNAs that have several other functions.

snRNA, or small nucleolar RNA, are found in the nucleus of eukaryotic cells and they function in defining the sites of nucleotide modifications.

snoRNA, or small nucleolar RNA, functions in defining the sites of nucleotide modification in rRNA.

gRNA, or guide RNA, functions by editing certain mRNAs.

tmRNA, which is a combination of tRNA and mRNA, functions by rescuing ribosomes that become "stuck" while mRNA is being translated and have lost their stop codons.

There are many types of RNA and each of these has their own unique function that is essential to the bodies everyday functioning and ability to do its jobs.

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