Which codon is not recognized by a tRNA molecule?

The codon that does not correspond to a tRNA molecule is UAA. This is because UAA is a stop codon, which signals the termination of protein synthesis during translation. In the genetic code, stop codons are not recognized by tRNA molecules since there is no corresponding tRNA that carries an amino acid for these codons. As a result, when the ribosome encounters a stop codon during translation, it does not add an amino acid; instead, it disassembles the translation machinery to complete the process of protein synthesis.

On the other hand, the codons AUG, UAC, and UAG all have specific roles in translation. AUG is the start codon that also codes for the amino acid methionine and is recognized by its corresponding tRNA. UAC codes for the amino acid tyrosine and is similarly recognized by its corresponding tRNA. UAG, while it is another stop codon, functions in a similar manner to UAA but is recognized by specific factors involved in translation termination rather than by a tRNA molecule.