There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that ________.
A) some tRNAs have anticodons that recognize 4 or more different codons
B) the rules for base pairing between the third base of a codon and tRNA are flexible
C) many codons are never used, so the tRNAs that recognize them are dispensable
D) the DNA codes for all 61 tRNAs, but some are then destroyed
E) competitive exclusion forces some tRNAs to be destroyed by nucleases

Question

Quizplus · Accepted Answer

The rules for base pairing between the third base of a codon and the tRNA can be flexible, allowing some tRNAs to recognize multiple codons. This is known as wobble base pairing and helps to explain how only 45 tRNAs are needed to decode all 61 mRNA codons.

There Are 61 MRNA Codons That Specify an Amino Acid