The Genetic Code

Translation is the final step of expression of genes those code for protein.the mRNA nucleotide sequence is translated into the amino acid sequence of a polypeptide chain.

Genetic code is the sequence of nucleotide over DNA. This help in making mRNA and then protein by joining amino acid together identified by tRNA.

Establishment of the Genetic Code

As it become common that DNA is a genetic material, scientist start functioning on how this information is transferred to next generation. For this they study DNA which contain a coded information. It is hidden in the sequence of nucleotide present in DNA. Sequence of A-G-C-T make a code which is transferred into the mRNA. mRNA move out from the nucleus of eukaryotic cell. This mRNA help in joining amino acids molecules joining together to form a polypeptide. So, here we can get a copy of protein who’s information is hidden in DNA in the coded form.

This is how DNA carry all the information from one generation to another.

Organization of the Code

The genetic code, present in RNA form. There is up to 6 different codons for a given amino acid. Only 61 codons are called as sense codons, those direct amino acid incorporation into protein. The remaining three codons (UGA, UAG, and UAA) are involved in the termination of translation and are called stop or nonsense codons.

Despite the existence of 61 sense codons, there are not 61 different tRNAs, one for each codon. The 5’ nucleotide in the anticodon can vary, but generally, if the nucleotides in the second and third anticodon positions complement the first two bases of the mRNA codon, an aminoacyl-tRNA with the proper amino acid will bing to the mRNA-ribosome complex.