The genetic code was originally deciphered, in part, by experiments in which synthetic polynucleotides with repeating sequences were used as mRNAs to direct protein synthesis in cell-free extracts. Under these conditions, ribosomes could be made to start translation anywhere within the RNA molecules, with no start codon necessary. What peptide would be made by translation from a synthetic mRNA made of the repeating dinucleotide CGCG…?
A. a polymer of arginine plus a polymer of alanine
B. the peptide Met–Arg–Ala–Arg–Ala…
C. a polymer of alanine: Ala–Ala–Ala…
D. a peptide containing alternating arginines and alanines
E. a polymer of arginine: Arg–Arg–Arg…