Final answer:
The wobble hypothesis specifically explains why there are 61 codons for the 20 amino acids, as some tRNAs can recognize multiple codons due to the flexible pairing at the third nucleotide position of the codon. This degeneracy maintains the efficiency and specificity of the genetic code.
Step-by-step explanation:
The wobble hypothesis accounts for the fact that there are 61 different codons that code for the 20 major amino acids, which is answer option 3. This hypothesis explains the degeneracy of the genetic code, particularly the phenomenon where the third nucleotide base in a codon, known as the 'wobble' base, can pair with multiple nucleotides, allowing for a more flexible codon-anticodon pairing. It is this flexibility that makes it possible for a limited number of tRNAs to recognize the 61 codons that encode amino acids.
Despite the existence of 64 different codons, only 61 are used to encode amino acids while the remaining three codons act as stop signals to terminate protein synthesis. Although a single amino acid can be coded by multiple codons due to this redundancy, called degeneracy, each codon codes for only one amino acid, demonstrating the code's specificity and unambiguity. The wobble hypothesis is a critical piece of our understanding of genetic translation and the efficiency of the standard genetic code (SGC).