Final answer:
The statement that most amino acids are specified by a unique triplet code is false. While each codon corresponds to only one amino acid, many amino acids are encoded by multiple codons due to the redundancy of the genetic code, providing a protective mechanism against mutations.
Step-by-step explanation:
Is Each Amino Acid Specified by Only One Unique Triplet Code?
The statement that most amino acids are specified by only one unique triplet code is false. The genetic code is known for being both unambiguous and redundant, meaning that each codon corresponds to only one amino acid, but several codons can specify the same amino acid. For instance, the amino acid threonine is encoded by four different codons: ACU, ACC, ACA, and ACG. This redundancy, often referred to as the code's degeneracy, provides a buffer against mutations by allowing a single-nucleotide change to result in the same amino acid or one with a similar biochemical property, thereby often preserving protein function.
There are 64 possible codons, but only 20 standard amino acids, with some amino acids like glycine and arginine being represented by multiple codons, while others such as methionine and tryptophan are encoded by a single codon. The redundancy of the genetic code plays a significant role in reducing the detrimental effects of mutations, ensuring robustness in the protein synthesis process.