Transcription in biology is a multi-stage process of reading information from DNA, which is a component of protein biosynthesis in a cell. Nucleic acid is the carrier of genetic information in the body, so it is important to correctly decipher it and transfer it to other cellular structures for further assembly of peptides.
Definition of "transcription in biology"
Protein synthesis is a basic vital process in any cell of the body. Without the creation of peptide molecules, it is impossible to maintain normal life activity, because these organic compounds are involved in all metabolic processes, are structural components of many tissues and organs, play a signaling, regulatory and protective role in the body.
The process from which protein biosynthesis begins is transcription. Biology briefly divides it into three stages:
- Initiation.
- Elongation (growth of the RNA chain).
- Termination.
Transcription in biology is a whole cascade of step-by-step reactions, as a result of which molecules are synthesized on the DNA templateRNA. Moreover, not only informational ribonucleic acids are formed in this way, but also transport, ribosomal, small nuclear and others.
Like any biochemical process, transcription depends on many factors. First of all, these are enzymes that differ between prokaryotes and eukaryotes. These specialized proteins help to initiate and carry out transcription reactions accurately, which is important for high-quality protein output.
Transcription of prokaryotes
Since transcription in biology is the synthesis of RNA on a DNA template, the main enzyme in this process is DNA-dependent RNA polymerase. In bacteria, there is only one type of such polymerase for all molecules of ribonucleic acid.
RNA polymerase, according to the principle of complementarity, completes the RNA chain using the template DNA chain. This enzyme has two β-subunits, one α-subunit and one σ-subunit. The first two components perform the function of forming the body of the enzyme, and the remaining two are responsible for retaining the enzyme on the DNA molecule and recognizing the promoter part of the deoxyribonucleic acid, respectively.
By the way, the sigma factor is one of the signs by which this or that gene is recognized. For example, the Latin letter σ with index N means that this RNA polymerase recognizes genes that turn on when there is a lack of nitrogen in the environment.
Transcription in eukaryotes
Unlike bacteria,animal and plant transcription is somewhat more complicated. Firstly, in each cell there are not one, but as many as three types of different RNA polymerases. Among them:
- RNA polymerase I. It is responsible for the transcription of ribosomal RNA genes (with the exception of the 5S RNA subunits of the ribosome).
- RNA polymerase II. Its task is to synthesize normal informational (matrix) ribonucleic acids, which are further involved in translation.
- RNA polymerase III. The function of this type of polymerase is to synthesize transport ribonucleic acids, as well as 5S-ribosomal RNA.
Secondly, for promoter recognition in eukaryotic cells, it is not enough to have only polymerase. Transcription initiation also involves special peptides called TF proteins. Only with their help can RNA polymerase sit on DNA and begin the synthesis of a ribonucleic acid molecule.
Transcription value
The RNA molecule, which is formed on the DNA template, subsequently joins the ribosomes, where information is read from it and a protein is synthesized. The process of peptide formation is very important for the cell, because without these organic compounds, normal life is impossible: they are, first of all, the basis for the most important enzymes of all biochemical reactions.
Transcription in biology is also a source of rRNA, which are part of ribosomes, as well as tRNA, which are involved in the transfer of amino acids during translation to these non-membranestructures. snRNAs (small nuclei) can also be synthesized, the function of which is to splice all RNA molecules.
Conclusion
Translation and transcription in biology play an extremely important role in the synthesis of protein molecules. These processes are the main component of the central dogma of molecular biology, which states that RNA is synthesized on the DNA matrix, and RNA, in turn, is the basis for the beginning of the formation of protein molecules.
Without transcription, it would be impossible to read the information that is encoded in triplets of deoxyribonucleic acid. This once again proves the importance of the process at the biological level. Any cell, be it prokaryotic or eukaryotic, must constantly synthesize new and new protein molecules that are needed at the moment to maintain life. Therefore, transcription in biology is the main stage in the work of each individual cell of the body.
