Final answer:
The sequence of the start codon that initiates translation on an mRNA molecule is AUG. This codon is essential for beginning the synthesis of a polypeptide and additionally codes for methionine.
Step-by-step explanation:
The sequence of the start codon on an mRNA molecule that initiates translation is AUG. This specific codon also codes for the amino acid methionine. In eukaryotes, the initiation complex locates this start codon after binding to the 7-methylguanosine cap on the mRNA and scanning for the AUG sequence. Kozak's rules inform us that certain nucleotides around AUG help determine its selection as the start site for translation. When the ribosome encounters the start codon AUG, it begins synthesizing a polypeptide chain, adding amino acids in the order specified by the mRNA codons until a stop codon signals the end of translation.