Central Dogma of Biology

 

Central Dogma of Biology

The ‘Central Dogma’ is the process by which the instructions in DNA are converted into a functional product. The process illustrates the flow of genetic information in cells, DNA replication, and coding for the RNA through the transcription process, and further RNA codes for the proteins by translation. Now let's learn about each stage in central dogma one by one.

Replication (From DNA to DNA)

DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential process because, whenever a cell divides, the two new daughter cells must contain the same genetic information, or DNA, as the parent cell.

Transcription (From DNA to mRNA)

Transcription is the process by which information is transferred from one strand of the DNA to RNA by the enzyme RNA Polymerase. The DNA strand which undergoes this process consists of three parts namely a promoter, a structural gene, and a terminator. The DNA strand that synthesizes the RNA is called the template strand and the other strand is called the coding strand. The DNA-dependent RNA polymerase binds to the promoter and catalyzes the polymerization in the 3′ to 5′ direction. As it approaches the terminator sequence, it terminates and releases the newly synthesized RNA strand. The newly released RNA strand further undergoes post-transcriptional modifications.

Translation (From mRNA to protein)

Translation is the process by which the RNA codes for specific proteins. It is an active process that requires energy. This energy is provided by the charged tRNA molecules. Ribosomes initiate the translation process. The ribosomes consist of a larger subunit and a smaller subunit. The larger subunit, in turn, consists of two tRNA molecules placed close enough so that peptide bonds can be formed at the expense of enough energy.

The mRNA enters the smaller subunit which is then held by the tRNA molecules of the complementary codon present in the larger subunit. Thus, two codons are held by two tRNA molecules placed close to each other and a peptide bond is formed between them. As this process repeats, long polypeptide chains of amino acids are synthesized. Learn about the technical details of the three crucial biomolecular processes that we just learned about by viewing the following video: