Question

The genetic code is said to be a triplet code. What does this mean and why is it important?

Answer 1

A triplet code means that genetic information is read in groups of three consecutive nitrogenous bases, called codons, to specify a single amino acid.

1. Adequate Combinations: Since there are 20 different amino acids but only 4 types of bases (A, U, G, C), a single-base code (4¹ = 4) or a doublet code (4² = 4) would not provide enough unique combinations. A triplet code (4³ = 64) provides more than enough combinations to cover all 20 amino acids.
2. Biological Precision: This system ensures that the complex instructions for building proteins are translated accurately from DNA/RNA into the correct polypeptide chain.
3. Redundancy and Signalling: The “extra” 44 codons allow the code to be degenerate (multiple codons for one amino acid), which protects against some mutations, and provides specific start and stop signals for translation.