Since there are amino acids and
possibilitiesof mRNA codons, is
expected some acids to be
by more than codon. And
that happens.

Not all codons however codify
acids. Three of , UAA, UGA and
, work on information the last
amino of a polypeptide under
productions was bound, i.e.,
they the end of polypeptide
synthesis.These codons called
terminal codons. codon AUG
codifies amino acid methionine
at the same it signals the
of the synthesis a
polypeptide chain ( is an initialization
).

In prokaryoticcells there a sequence
called -Dalgarno sequence (in
general )in the position that
the initialization codon .
The function of sequence is
distinctnessbetween initialization
AUG and AUG codons of RNA.