The genetic code is the list of all codons and the amino acids that they encode. Main features of the genetic code were proved in genetic experiments carried out by F.Crick and collaborators:
•Translation starts from a fixed point
•There is a single reading frame maintained throughout the process of translation
•Each codon consists of three nucleotides
•Code is nonoverlapping
•Code is degenerate: each amino acid is specified by more than one codon
Characterstics of Genetic code
I.Triplet in nature——ex UUU codes for phenylalanine
II.Nearly universal——UGA is stop codon in bacteria, plants and animals but in mitochondria it codes for tryptophan
III.Non Overlapping——-a nitrogenous base is constituent of only one codon
IV.Comma less….read in continuous fashion
V.Unambiguous in nature——-one codon codes for specific type of amino acid
VI.Degeneracy of genetic code———single amino acid is coded by more than one type of codon
●In prokaryotes AUG act as start codon and add N-Formyl Methionine and inside the chain it adds methionine
In eukaryotes AUG at start position adds methionine where as in between ither nucleotides it also adds methionine
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