Final answer:
Only one polypeptide sequence would be generated from the repeating mRNA sequence given, as it corresponds to a single amino acid, serine, in a consistent pattern.
Step-by-step explanation:
When the synthetic mRNA with the repeating sequence 5' UCCUCCUCC 3' is translated in a cell-free system, only one polypeptide sequence would be generated. This is because the sequence is repeating and will consistently code for the same amino acids in a given reading frame. Translation using the genetic code will convert the mRNA sequence into a polypeptide chain, where each triplet codon specifies a single amino acid. The sequence given translates to the amino acid serine repeated, as UCC is the codon for serine.