Final answer:
To establish which amino acid corresponds to a particular codon, a series of foundational experiments were historically necessary. Now, we already know that codons are triplets, there are 64 possible codons, and the genetic code allows for degeneracy, which makes cells more robust against mutations. No further experiments would require repeating since past research has identified the amino acids each of the 64 codons encodes.
Step-by-step explanation:
To understand how many experiments would have to be conducted to determine which amino acid a certain codon codes for, it's important to grasp the principles of the genetic code. Originally, scientists had to deduce how a molecule with only 4 different nucleotides (adenine, cytosine, guanine, and uracil in RNA) could specify the sequence for the 20 amino acids in proteins. If each nucleotide coded for a single amino acid, only 4 amino acids could be coded, which is insufficient.
If codons were two nucleotides long, there would still only be 4², or 16 possible combinations, which falls short for 20 amino acids. Thus, codons are groups of 3 nucleotides in length, allowing for 4³, or 64 different possibilities. This number is more than adequate to encode all 20 amino acids, with some redundancy, which is referred to as the degeneracy of the genetic code.
Additionally, this degeneracy contributes to the robustness of cells against mutations, particularly at the third position of a codon, known as the wobble position. In conducting an experiment to determine the amino acid a particular codon specifies, researchers would not need to test all 64 codons, as the theoretical framework and previous experimental work have laid the groundwork for codon assignments. Through techniques like Nirenberg and Leder's triplet binding assay or the use of synthetic RNA sequences, each of the 64 codons has already been matched to its corresponding amino acid.