RNA – Structure, Functions and Types

Introduction

The RNA – structure or the ribonucleic Acid molecule of the cell is similar to the DNA with a basic structural difference, i.e. the RNA molecule is single-stranded whereas the DNA is double-stranded. The RNA molecule is composed of alternative sugar (ribose) and phosphate groups which form the backbone of the RNA’s structure.

The structure of RNA modifies itself to form complex structures by folding into itself and adding modified base structures, which further affects the functioning of the RNA molecule. 

Composition of RNA

The RNA structure consists of ribose nucleotides which are essentially nitrogenous bases attached to a ribose sugar which are connected by phosphodiester bonds.

The following bases are attached to the alternating sugar structure of the RNA:

• Guanine (G)
• Uracil (U)
• Cytosine (C)
• Adenine (A)

RNA structures are used by the cells to carry messages, transfer information, and carry amino acids to the site of translations, which manifests the formation of protein chains.

RNA Secondary Structure

The RNA – structure molds into the secondary or tertiary structure of the cell, which controls the diverse functions and activities performed by the cells. These RNA structures form various combinations, leading to different activities’ functioning.

At the core stage, the RNA – structure consists of nucleotides that are found in two different states, i.e. paired and unpaired. The RNA – structures interact on a base to base level at the paired stage.

Types of RNA Structures

The RNA or ribonucleic acid structures are present in various living organisms and viruses. The RNA structures are mainly single-stranded, but in certain specific cases, the RNA structures can also have a double strand.

An RNA virus utilises the RNA – structures or molecules instead of DNA molecules as its genetic base, and this phenomenon has the potential to lead to long-term illnesses and diseases in humans.

The functioning of the RNA and its synthesis is particularly dependent on:

• Eukaryotes
• Prokaryotes

Transcription: The process of generation of RNA structures from DNA.

Translation: The process of synthesis or formation of protein by the RNA structures.

There are certain specific RNA structures responsible for controlling the expression of the genes, and they also have the potential to act as therapeutic agents for various human diseases and illnesses.

Now, three major types of RNAs are responsible for the process of protein synthesis, such as mRNA (also known as the messenger RNA), tRNA (also known as the transfer RNA), and rRNA (also known as the ribosomal RNA).

1. mRNA (messenger RNA)

The mRNA is encrypted from the DNA, and it consists of a genetic blueprint that enables the formation of protein. The prokaryotes mRNA can synthesize protein production immediately, and it does not need to be processed or matured, unlike the eukaryotes mRNA.

The eukaryotic mRNA requires undergoing the process of maturation to synthesize the protein. A fresh batch of encrypted mRNA is known as pre-mRNA in the eukaryotes. In modern science, researchers comprehend mRNA’s functions and properties for developing anti-cancer cures due to its property of modifying cells.

1. tRNA (transfer RNA)

The tRNA performs the task of translating the protein from the mRNA. The main purpose of tRNA is to carry the amino acid to the site of the ribosome complex through the enzymes called- Aminoacyl-tRNA synthetases. This enzyme helps in loading the correct amount of amino acids in the tRNA to be later on synthesized into protein.

1. rRNA (ribosome RNA)

The rRNA enables the formation of ribosomes which is essential for the production of proteins. A whole ribosome consists of large and small ribosomal subunits. A ribosome consists of an exit (E), an acceptor (A) site, and a peptidyl (P) to combine the aminoacyl-tRNAs, and it connects the amino acids to form polypeptides.

RNA Chemical Structure

The RNA is formerly a single strand structure encrypted from the DNA. But, in certain situations, the presence of self-complementary sequences in the RNA leads to the intra-chain base-pairing and folding of the RNA molecule into complex structures, which can involve the formation of helices and bulge-like protrusions.

The former structure of the RNA is crucial for the functioning, stability, and production of ribose sugar and nitrogenous bases, which are later modified and transformed into various chemical chains and cellular enzymes.

These changes and modifications in the RNA molecules lead to the formation of distant chemical bonds between the RNA – structures which further strengthens the links between the distant RNA structures.

RNA structures with weaker modifications can collapse or be destroyed easily.

Conclusion

RNA or ribonucleic acid is transcribed from the DNA with the basic structure of being single-stranded. The RNA – structure is complex, and it is crucial for protein formation for the cells. RNA can be categorized into mainly three types, i.e. mRNA, tRNA, and rRNA. The mRNA is responsible for protein synthesis, the tRNA is responsible for carrying the amino acid to a specific site for protein synthesis, and the rRNA is responsible for ribosome formation, which further helps in the process of synthesis of protein.