How many unique codons are present in the genetic code?

The correct choice of 64 unique codons in the genetic code comes from the way codons are formed during protein synthesis. Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids or signal the termination of protein synthesis.

Since there are four different nucleotide bases (adenine, cytosine, guanine, and uracil), and each codon consists of three nucleotides, the total number of possible combinations can be calculated as 4^3 (4 raised to the power of 3). This results in 64 possible codons.

Among these 64 codons, 61 codons are used to code for the 20 standard amino acids, while the remaining three codons are designated as stop codons, which signal the termination of translation. Therefore, the understanding that there are 64 unique codons is fundamental to genetics as it explains how the genetic code can provide instructions for synthesizing a vast array of proteins necessary for life.