Although there are 61 sense codons, human cells contain far fewer distinct tRNA species. This economy is explained by:

• A Post-transcriptional editing of anticodons into all possible sequences
• B Use of overlapping reading frames within a single mRNA
• C Wobble pairing, allowing one anticodon base to pair with multiple codon third bases ✓
• D Recruitment of uncharged tRNAs that are charged later on the ribosome

Explanation

Crick's wobble hypothesis states that the first base of the anticodon (wobble position) pairs less strictly and can recognize two or three different third bases of codons. Modified bases such as inosine extend this flexibility further. As a result, roughly 40 to 50 tRNA species suffice to read all 61 sense codons. Anticodon editing does not occur, reading frames do not overlap within a normal mRNA, and charging happens before ribosome binding.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.