State the salient features of genetic code.
 

The salient features of genetic code are as follows:
$(i)$  The codon is triplet. $61$ codons code for amino acids and $3$ codons do not code for any amino acids, hence they function as stop codons.
$(ii)$  One codon codes for only one amino acid, hence, it is unambiguous and specific.
$(iii)$  Some amino acids are coded by more than one codon, hence the code is degenerate.
$(iv)$  The codon is read in $mRNA$ in a contiguous fashion. There are no punctuations.
$(v)$  The code is nearly universal: for example, from bacteria to human $UUU$ would code for Phenylalanine (phe). Some exceptions to this rule have been found in mitochondrial codons, and in some protozoans.
$(vi)$  $AUG$ has dual functions. It codes for Methionine (met) , and it also act as initiator codon.