What is the wobble effect in relation to tRNA?

The wobble effect refers specifically to the flexible base-pairing that occurs at the third position of a codon in mRNA, allowing a single tRNA molecule to recognize multiple codons that code for the same amino acid. This phenomenon is particularly important because it helps to explain why there are fewer tRNA molecules than there are codons. The ability for the third nucleotide in a codon to form non-standard base pairs means that the genetic code can be efficiently translated without needing a unique tRNA for every codon, thus increasing the efficiency of protein synthesis.

In the context of the options provided, the correct choice correctly identifies this tolerance for variations in the third base of codons, which is a hallmark of the wobble effect. This feature plays a critical role in maintaining the efficiency and fidelity of the translation process in protein synthesis.