Final answer:
There are 64 possible amino acids that might be coded for by mRNA, calculated as 4³ (4x4x4) due to the triplet nature of a codon and the availability of four bases.
Step-by-step explanation:
Based on the triplet nature of a codon and the presence of four possible bases (A, U, G, C), there are 64 possible amino acids that can be coded for by mRNA. The codon is a three-nucleotide sequence, and each nucleotide can have one of four different bases. Therefore, the total number of possible codons is 4³ or 4 x 4 x 4, which equals 64.
Out of the 64 possible codons, three are stop codons which signal the termination of protein synthesis. The remaining 61 codons code for the addition of amino acids to the polypeptide chain during the process of translation. Interestingly, while there are 64 possible combinations, there are only 20 common amino acids. This means that some amino acids are specified by more than one codon.