Final answer:
The codon AUG serves as the start signal or start codon for translation and initiates the process of protein synthesis.
Step-by-step explanation:
The codon AUG serves as the start signal or start codon for translation. In addition to coding for the amino acid methionine, the AUG codon is responsible for initiating the process of translation in mRNA. It sets the reading frame and marks the beginning of the protein synthesis.