Here's why:
* Start codon: In mRNA, the codon AUG signals the start of protein synthesis.
* Methionine's role: Methionine is the only amino acid encoded by the AUG codon.
* Initiator tRNA: A special tRNA molecule, called the initiator tRNA, carries methionine and binds to the AUG start codon. This starts the process of translation, where the genetic code is translated into a protein.
Important Note: While methionine is always the first amino acid incorporated, it may be removed from the final protein in some cases after translation.
