Campbell Biology Concepts & Connections Practice Test

Genetic code uses triplet codons, each formed from the four nucleotide bases. Because there are 64 possible triplets but only about 20 amino acids, most amino acids are encoded by more than one codon, giving redundancy in the code. This redundancy is why the statement that many amino acids are coded by more than one codon is true. It’s also why the other options don’t fit: codons are three bases long, not four; there are stop codons to terminate translation, so the idea that there are no stop codons is false; and having multiple codons per amino acid is the hallmark of the degeneracy of the genetic code.