Final answer:
The feature not characteristic of tRNA molecules is Codon, as tRNAs have anticodons that pair with mRNA codons to ensure correct amino acid placement in protein synthesis.
Step-by-step explanation:
The feature that is not a characteristic of transfer RNA (tRNA) molecules is the Codon. Codons are found on messenger RNA (mRNA) and are the sequences that tRNA molecules recognize and bind to via their anticodons. Transfer RNAs have an anticodon that matches the codons on mRNA to ensure that the correct amino acid is added to the growing polypeptide chain. Additionally, tRNA molecules feature a cloverleaf structure, stabilized by complementary base pairing, and have an amino acid acceptor stem with a 3'' single-stranded region that holds the amino acid. The presence of codons on tRNA is incorrect because codons are part of mRNA, not tRNA.