In addition to cell-free translation experiments with mixtures of synthetic RNAs, efforts to decipher the genetic code included
A cell-free translation of copolymers and triplet-binding assays
B transcription assays and cell-free translation of copolymers
C DNA-RNA binding assays and triplet-binding assays
The correct answer and explanation is:
The correct answer is A: cell-free translation of copolymers and triplet-binding assays.
To explain further, deciphering the genetic code was a monumental task in molecular biology, especially during the mid-20th century when researchers sought to understand how sequences of nucleotides in RNA (the codons) translated into the sequence of amino acids in proteins. This translation process, known as protein synthesis, was the focus of multiple experimental strategies.
One important approach involved cell-free translation systems, where researchers could mix synthetic RNA sequences with ribosomes and other translation machinery to observe the synthesis of proteins without using living cells. These experiments were crucial for understanding how specific RNA sequences encoded proteins, as they allowed researchers to control and observe the process in a test tube setting.
In addition to this, copolymer experiments were used in which synthetic RNAs made from repeating nucleotides (e.g., repeating the same two or three bases) were used to determine which amino acids were incorporated into proteins. These copolymer experiments were valuable because they made it possible to systematically analyze how different sequences of nucleotides corresponded to different amino acids in proteins.
Another key technique was triplet-binding assays, which were designed to identify the codons that matched specific amino acids. In these assays, researchers used synthetic triplets of RNA (codons) and tested which amino acids could bind to specific triplet combinations, thus helping to map the codons of the genetic code to their corresponding amino acids.
Together, these two experimental approaches—cell-free translation of copolymers and triplet-binding assays—provided critical insights into how the nucleotide sequence in RNA dictated the sequence of amino acids in proteins, leading to the eventual establishment of the genetic code.