Central dogma

The central dogma in molecular biology shows the passage of genetic information from DNA to RNA to protein. It is understood as the method of converting DNA information into a functioning product.

It is considered that the information provided in DNA is necessary for the formation of all proteins and that RNA acts as a messenger, carrying information through the ribosomes. Let us talk about central dogma definition, facts, steps involved etc. 

What is central dogma?

Central Dogma is the process by which genetic information present in DNA is converted into a functional product,i.e., Proteins. It displays the circulation of genetic information within cells, DNA replication and RNA coding via transcription, followed by RNA coding for proteins by translation. All this happens through a sequence of interactions.For example let’s understand by the framework of Biopolymers. Proteins, RNA and DNA are the three major categories of biopolymers, which are further split into general transfers, unknown transfers and special transfers.

In the laboratory, special transfers occur in rare circumstances. Almost every cell undergoes general transfer. It refers to the regular flow of data that occurs due to transcription and translation. Unknown transfers are reported to be extremely rare.

Facts about central dogma

• In the grand scheme of things, molecular biology’s basic premise is a clarification of how genetic information flows inside a biological scheme.
• It was first specified by Francis Crick in 1958. 
• When ‘information’ has penetrated protein, it cannot be recovered. More specifically, information can be moved from nucleic acid to nucleic acid or from nucleic acid to protein, but not from protein to protein or from protein to nucleic acid.

Steps involved

Replication, transcription and translation are used by all cells to keep a record of their genetic information and to transform genetic information encoded in DNA into gene products, which are either RNAs or proteins based on the gene.

Replication and transcription take place in the nucleus of eukaryotic cells, or cells with a nucleus, while translation takes place in the cytoplasm outside of the nucleus. Prokaryotic cells, or cells without a nucleus, undergo all three processes in their cytoplasm.

Transcription process – DNA to RNA

The genetic information is transferred from one single strand of DNA to RNA through the transcription process. The initial stage of gene expression occurs in this process, where the DNA stretch is translated into RNA. The enzyme RNA Polymerase helps complete this process. Terminator, structural gene and promoter are the three sections of the single participant strand of DNA.

The template strand is one of two DNA strands that aid in creating RNA, while the coding strand is the other. Following that, RNA Polymerase binds to the promoter. This process is known as polymerisation.

Some of the transcripts utilize proteins, while others encode regulatory or structural RNAs. The transcribed gene produces mRNA or messenger RNA when it encodes a protein. This mRNA aids in the production of the protein during translation.

Translation process – RNA to protein

Messenger RNA is decoded and translated into a protein or polypeptide sequence during the translation process. This process is activated by the energy provided by charged tRNA. This is initiated by the ribosome, which is made up of two subunits, one larger and one smaller.

The peptide bond is formed by two tRNA molecules in the bigger subunit that are near together. A new polypeptide sequence is produced by decoding the genetic message of mRNA. The codons chain on the strand of mRNA is translated by tRNA.

tRNA continues to transmit free amino acid molecules from the cytoplasm to the ribosome’s growing polypeptide sequence until the chain can end at a codon on mRNA. The ribosome delivers the protein into the cell once it has finished forming it.

Replication 

It is the starting point for biological inheritance. It has the ability to duplicate a cell’s DNA. 

The process of converting DNA to RNA is known as transcription. The enzyme RNA polymerase converts a gene-encoding stretch of DNA into a corresponding RNA molecule. Protein is produced when mRNA is translated. The ribosome needs mRNA as a template to build a polypeptide shackle of amino acids. 

Genetic code

The genetic code is flooded with the necessary information that is required to make an RNA-based protein. Three nucleotides and four nitrogenous bases make up a triplet codon, which codes for one amino acid. As a result, 4 x 4 x 4 = 64 amino acids are available in total. In nature, there are a total of 20 amino acids.

The genetic code breaks down. This was explained by the genetic code properties, which state that a few amino acids are coded by many codons, causing them to degenerate. Each codon codes for a single unique amino acid, and the codes are universal across all organisms.

Three of the 64 codons are stop codons, which stop the transcription process and one is an initiator codon, AUG, which codes for Methionine.

Conclusion 

 The central dogma demonstrates the passage of genetic information from DNA to RNA to protein. It displays how information stored in DNA is passed to mRNA by the process of Transcription and how mRNA forms proteins by the process of Translation.