I think that, AGU and UCA both codes for the amino acid serine and so do the codons AGC , UCU, UCC, and UCG. The codon, CCA codes for proline and so do CCU, CCC and CCG. Therefore, any codons that do not code for the sequence serine-serine-proline would be different. For example, UUA-GAU-AAC, would code for a totally different amino acid sequence.
