What is transcription in biology? This is the stage of protein synthesis

Transcription in biology is a multi-step 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"

Synthesis of protein is the main vital process in any cell of the body. Without the creation of peptide molecules, it is impossible to maintain normal vital activity, since these organic compounds participate in all metabolic processes, are structural components of many tissues and organs, play a signal and regulating and protective role in the body.

The process from which protein biosynthesis begins is transcription. Biology briefly divides it into three stages:

1. Initiation.
2. Elongation (RNA chain growth).
3. Termination.

Transcription in biology is a whole cascade of step-by-step reactions, as a result of which RNA molecules are synthesized on the DNA matrix. And thus, not only information ribonucleic acids are formed, but also transport, ribosomal, small nuclear and other.

Like any biochemical process, transcription depends on many factors. First of all, these are enzymes that are different in prokaryotes and eukaryotes. These specialized proteins help initiate and conduct transcription reactions unerringly, which is important for the quality of protein production at the output.

Transcription of prokaryotes

Since transcription in biology is the synthesis of RNA on a DNA template, in this process the main enzyme is the DNA-dependent RNA polymerase. In bacteria, there is only one kind of such polymerases for all molecules of ribonucleic acid.

RNA polymerase complements the RNA chain by the complementarity principle, using the DNA template chain. This enzyme contains 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 components are responsible for the retention of the enzyme on the DNA molecule and recognition of the promoter part of deoxyribonucleic acid, respectively.

By the way, the sigma factor serves as one of the signs by which a particular gene is recognized. For example, the Latin letter σ with the index N means that this RNA polymerase recognizes genes that are included when there is a lack of nitrogen in the environment.

Transcription in eukaryotes

Unlike bacteria, in animals and plants transcription is somewhat more complicated. First, in each cell there are not one, but as many as three kinds of different RNA polymerases. Among them:

1. RNA polymerase I. It is responsible for the transcription of ribosomal RNA genes (except for 5S RNA subunits of the ribosome).
2. RNA polymerase II. Its task is to synthesize the normal information (matrix) ribonucleic acids, which later participate in the translation.
3. RNA polymerase III. The function of this type of polymerase is to synthesize the transport of ribonucleic acids, as well as 5S-ribosomal RNA.

Secondly, to recognize the promoter in eukaryotic cells it is not enough to have only polymerase. In the initiation of transcription also involved are special peptides, called TF-proteins. Only with their help, RNA polymerase can sit on DNA and begin the synthesis of a ribonucleic acid molecule.

The value of transcription

The RNA molecule, which is formed on the DNA matrix, is subsequently attached to the ribosomes, where information is read from it and the protein is synthesized. The process of peptide formation is very important for the cell, because Without these organic compounds, normal vital activity is impossible: they are primarily the basis for the most important enzymes of all biochemical reactions.

Transcription in biology is also a source of rRNA that are part of the ribosomes, as well as tRNAs that are involved in the transfer of amino acids during translation to these non-membrane structures. Also, miRNA (small nuclear) can be synthesized, the function of which is to splice all RNA molecules.

Conclusion

Translation and transcription in biology play an exceptionally important role in the synthesis of protein molecules. These processes are the main component of the central dogma of molecular biology, which says 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 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 every single cell in the body.