Final answer:
It is false that multiple aminoacyl-tRNA synthetases exist for each amino acid. There is at least one specific aminoacyl tRNA synthetase per amino acid to charge the corresponding tRNA with the correct amino acid.
Step-by-step explanation:
The statement that multiple aminoacyl-tRNA synthetases exist for each amino acid is false. At least one type of aminoacyl tRNA synthetase exists for each of the 20 amino acids. These enzymes are specific for their corresponding amino acids and ensure that each tRNA molecule is charged with the correct amino acid. The number of aminoacyl tRNA synthetases varies by species, but it is not multiple for each amino acid. Instead, each enzyme recognizes the unique structure of its corresponding tRNA and catalyzes the formation of a high-energy bond between the amino acid and adenosine monophosphate (AMP), a process known as 'charging' the tRNA.