(a) One codon codes for only one amino acid , hence , it is unambiguous and specific. The code is nearly universal : For example , fron bacteria to human UUU would code for Phenylalanine (Phe). Some exception to this rule have been found in mitochondrial codons and in some protozoans.
Some amino acids are coded by more than one codon hence , the code is degenerate .AUG has dual functions It codes for Methionie (met) and it also act as initiator codon.