Unravel the central dogma definition and its significance in genetics. Understand DNA’s role in protein synthesis. Dive in now!
Central Dogma is the basis of molecular biology. Here we’ll study the unidirectional steps through which the gene i.e. DNA expresses into a protein.
Central Dogma Definition:
DNA->mRNA->Protein
The above unidirectional path is the central dogma. DNA can replicate to produce it’s exact copies and the process is called as DNA replication.
RNA synthesis from DNA is called as Transcription. Here mRNA carries the genetic message for amino acids sequence on a polypeptide or protein.
The final step of Central dogma is the Translation. Here, polypeptide is synthesized from the genetic code of mRNA by Ribosomes.
DNA replication occurs inside the nucleus. Transcription also occurs inside the nucleus in eukaryotic cell. But, Translation occurs in the cytoplasm at the site of Ribosomes.
Reverse Central Dogma:
In some viruses like Retrovirus ex. HIV, the genetic material is the RNA. So, RNA is first Reverse transcribed into Copy DNA by enzyme, reverse transcriptase. Then, c-DNA is transcribed and translated to complete the Central Dogma.
Central Dogma in Prokaryote:
In prokaryotic cell, DNA replication is carried out by a groupof enzymes together called as Replisome. Among them enzyme DNA polymerase III is the main polymerising enzyme. Other enzyme called Helicase is the unwindase enzyme which starts the process at ori-site by firming Replication Fork. Helicase does so by breaking H-bonds between parent DNA strands.
Transcription is catalysed by enzyme called RNA polymerase which is a holoenzyme regulated by sigma-factor at initiation and by rho-factor at termination.
Translationis a dynamic process that is completed by the help of Ribosome,t-RNA and m-RNA.
Central Dogma in Eukaryote:
In Eukaryote central dogma is same but complex mechanism. Transcription needs 3 types of RNA polymerase enzymes. Also Post-transcriptional modification of pre-mRNA occurs by process called Splicing.
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