Final answer:
The statement is true; there is at least one specific aminoacyl-tRNA synthetase for each of the 20 amino acids, responsible for charging the tRNA with the correct amino acid.
Step-by-step explanation:
The statement that only one aminoacyl-tRNA synthetase exists for each amino acid is true. Aminoacyl-tRNA synthetases are enzymes responsible for attaching amino acids to their corresponding tRNA molecules, a process known as "charging" the tRNA. There is at least one specific aminoacyl-tRNA synthetase for each of the 20 amino acids. The exact number of these enzymes may vary among different species.
The tRNA molecules, with their specific anticodon sequences, are recognized by their corresponding aminoacyl-tRNA synthetases. The enzyme catalyzes the attachment of an amino acid to its tRNA by first binding and hydrolyzing ATP to form a high-energy bond. This crucial reaction facilitates the subsequent incorporation of the amino acid into the growing polypeptide chain during protein synthesis.