Final answer:
In addition to cell-free translation experiments with synthetic RNAs, efforts to decipher the genetic code included fractionating E. coli to identify protein synthesis components and experiments adding amino acids to tRNAs to establish codon-amino acid associations.
Step-by-step explanation:
In efforts to decipher the genetic code, scientists conducted cell-free translation experiments with mixtures of synthetic RNAs and identified which components were required to synthesize proteins in vitro. One of the landmarks in this venture was the experiment designed by Marshall Nirenberg and Heinrich J. Matthaei who fractionated E. coli and decoded the first triplet, leading to the identification of specific amino acids associated with certain codons. Significant breakthroughs in understanding the genetic code continued with Nirenberg and Philip Leder's experiments, which involved adding individual amino acids to separate test tubes containing tRNAs, thereby facilitating the synthesis of specific aminoacyl-tRNAs and helping to establish the remaining codons.
Additional approaches included the theoretical study and evolution of genetic code, which was connected to the roles of tRNAs and their development. By examining the molecular interactions between amino acids and RNAs, researchers advanced the understanding of the origins of genetic code and translation mechanisms.