0The concept of cental dogma, can be in short noted as :
Transcription + Translation
- Transcription is formation of RNA from DNA.
- Translation is formation of products from RNA.
Dna -------------------> Rna ------------------> Proteins
Transcription:
The copying of nucleotide sequences on dna to rna is called as transcription. The process of transcription is done inside the nuleus. That means nucleus the machinery of transcription.The process of transcription is characterised by the enzyme ' RNA Polymerase '.
The Rna produced from Dna is antiparallel to the dna strand & is named as 'Rna - Transcript '.
Steps involved:
- The part of dna which is to be transcribed acts as a promoter.
- Rna polymerase binds to promoter (CHAIN INITIATION).
- Transcription bubble is created & double strand of dna unwinds.
- Rna Nucleotides are added by Rna polymerase to one of the unwinded strands of dna (CHAIN ELONGATION).
- RNA chain elongates along the DNA strand.
- RNA-DNA hybrid is formed (CHAIN TERMINATION).
- Hydrogen bonds are broken, freeing the newly formed Rna-transcript.
Translation:
This rna formed in the nucleus is processed and is converted to messenger rna (m-Rna).
m-Rna, from the nucleus is transported to cytoplasm for protein synthesis. This process only is termed as translation.
The process of translation or decoding of information present in m-Rna is done by the ribosomes. This translation involved 3 steps namely:
-
Chain Initiation: Attachment of mrna to ribosomal unit, followed by attachment of t-rna.
-
Chain Elongation: T-rna keeps on adding aminoacids reading mrna code, also peptide bond formation is observed among aminoacids.
-
Chain Termination: On reaching nonsense codons / stop codons, ribosomal unit releases the polypeptide chain.
