Final answer:
The first codon translated in the mRNA sequence 5'-GGAAUGAAACAGGAACCC-3'is AUG, which codes for methionine. This codon sets the reading frame for the rest of the translation.
Step-by-step explanation:
The first codon translated in the mRNA sequence 5'-GGAAUGAAACAGGAACCC-3' is AUG, which is also known as the start codon. In the context of eukaryotic translation, Kozak's rules help to find the starting AUG codon. According to Kozak's rules, the consensus sequence 5'-gccRccAUGG-3', where R stands for a purine (A or G), enhances the efficiency of translation initiation at the AUG start codon. This specific mRNA sequence contains the start codon AUG, which codes for the amino acid methionine and sets the reading frame for translation.
The process of translation involves reading the mRNA molecule codon by codon, from the 5' to the 3' end, beginning from the start codon. Following the AUG start codon, translation continues until a stop codon (UAG, UGA, or UAA) is reached. Stop codons do not encode for any amino acids and signal the termination of protein synthesis. Therefore, when analyzing an mRNA sequence for the amino acid sequence it codes for, one would start translation at the AUG codon and continue until a stop codon is encountered. This allows for the determination of the peptide length and the specific sequence of amino acids that compose the protein being synthesized from the mRNA.