Where is the codon found in the process of protein synthesis?

The correct choice is found on mRNA, which is crucial in the process of protein synthesis. During transcription, a gene on the DNA is copied to produce messenger RNA (mRNA), which contains the codons. These codons are specific sequences of three nucleotides that correspond to particular amino acids, effectively serving as the instructions for assembling proteins.

In the subsequent translation process, the mRNA codons are recognized by transfer RNA (tRNA) molecules, which bring the appropriate amino acids to the ribosome, where proteins are synthesized. This critical functionality of mRNA establishes it as the carrier of genetic information from the DNA to the ribosomal machinery that constructs proteins based on that information.