What is transcription in biology? This is a protein synthesis step.

Transcription in biology is a multistage 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 decipher it correctly and transfer it to other cellular structures for further assembly of peptides.

The definition of "transcription in biology"

Protein synthesis is the main vital process in any cell of the body. Without the creation of peptide molecules, it is impossible to maintain normal life, because these organic compounds are involved in all metabolic processes, are structural components of many tissues and organs, and play a signal and regulatory and protective role in the body.

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

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

Transcription in biology is a cascade of step-by-step reactions, as a result of which RNA molecules are synthesized on a DNA matrix. Moreover, in this way not only informational ribonucleic acids are formed, 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 in prokaryotes and eukaryotes. These specialized proteins help to initiate and carry out transcription reactions accurately, which is important for high-quality protein production at the output.

Transcription of Prokaryotes

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

RNA polymerase complements the RNA strand using the template DNA strand by the principle of complementarity. 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 other two 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 is one of the signs by which one or another gene is recognized. For example, the Latin letter σ with the index N means that this RNA polymerase recognizes genes that turn on when there is a lack of nitrogen in the environment.

Eukaryotic transcription

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

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

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

The meaning of transcription

The RNA molecule that forms 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, which are part of ribosomes, as well as tRNA, which are involved in the transfer of amino acids during translation to these non-membrane structures. SnRNAs (small nuclear) can also be synthesized, the function of which is to splicing 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 start 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, whether it is prokaryotic or eukaryotic, must constantly synthesize new and new protein molecules that are needed at the moment to maintain vital functions. Therefore, transcription in biology is the main stage in the work of each individual cell in the body.