Answer: the aminoacyl tRNA synthetase
Explanation:
Before an amino acid can be incorporated into the growing polypeptide chain in the ribosomes, they must first recognize and be attached to a their cognate tRNAs through a process called tRNA charging/loading. This process also called aminoacylation is aided by the aminoacyl tRNA synthetases also called tRNA ligases. Failure of the enzymes to carry out the correct charging are determined resulting in cellular dysfunctions. The process occurs in 2 steps
1. The enzymes binds ATP to the amino acid to form a complex of amino acid-AMP.
2. The amino acid is then linked with tRNA and the AMP is released this the tRNA is "charged" and ready to function