What is RNA:
RNA is the acronym for ribonucleic acid, a macromolecule essential for many biological functions.
As the name implies, RNA is a nucleic acid (just like DNA) and works in the regulation, coding, and decoding of genes. These acids, together with carbohydrates, lipids and proteins, make up the group of indispensable substances for all life forms.
The main function of RNA is to produce proteins from information acquired from DNA. For this reason, one of the great premises of molecular biology is that “DNA makes RNA make proteins.”
RNA is synthesized from DNA through the transcription process. This process is started with an enzyme called RNA polymerase, which promotes the opening of DNA and ensures the pairing of nucleotides to be transcribed.
RNA is made up of a chain of smaller substances called nucleotides. In RNA, nucleotides are composed of riboses, phosphates and nitrogenous bases, which are subdivided into:
- Purines: adenine (A) and guanine (G);
- Pyrimidines: cytosine (C) and uracil (U).
Unlike DNA, RNA is usually formed by a single strand (single strand). However, it is common for this single ribbon to bend around itself, bringing complementary nitrogen bases together and creating pairings. Thus, it ends up forming a three-dimensional structure similar to DNA.
RNA Types and Their Functions
There are three types of RNA: messenger (mRNA), ribosomal (rRNA) and transporter (tRNA).
Messenger RNA is the molecule responsible for bringing genetic information from DNA to the cytoplasm.
When a cell requires the production of a particular protein, DNA initiates the transcription process by which the genetic code is copied, thereby synthesizing a mRNA strip. This RNA acts as a moving copy of the DNA that carries the message to the cytoplasm and informs the type of protein that should be produced.
Ribosomal (or ribosomal) RNA is the substance that makes up approximately 60% of the ribosome, the organelle in which protein synthesis occurs. Its function is to assist in the translation of information brought by messenger RNA.
Ribosomal RNA is synthesized in a dense region located in the cell nucleus called the nucleolus. As the main ribosome component, rRNA is essential for all organelle functions, especially for the correct pairing between messenger RNA and carrier RNA.
Transport (or transfer) RNA is the molecule responsible for bringing amino acids to the ribosome to aid in protein synthesis.
When messenger RNA informs the type of protein to be produced, ribosomal RNA assists in the transfer of information to carrier RNA. Based on codons (sequence of three nitrogenous bases), the genetic code is identified and tRNA is responsible for transporting compatible amino acids for protein production.
Small interfering RNA
Sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA molecules. Small interfering Ribonucleic Acid or siRNA, 20-25 base pairs in length, similar to miRNA, and operating within the RNA interference pathway.
In summary, the main characteristics of RNA are:
- works in the regulation, coding and decoding of genes;
- Its main function is to produce proteins;
- they are formed by riboses, phosphates and nitrogenous bases;
- It is formed by a simple chain (a single ribbon);
- can be classified into messenger RNA, ribosomal RNA and carrier RNA.
- messenger RNA is responsible for bringing DNA information to the cytoplasm;
- ribosomal RNA assists in translating the information brought from DNA;
- carrier RNA carries amino acids to the ribosome to aid in protein synthesis.