Final answer:
An aminoacyl tRNA synthetase attaches an amino acid to the tRNA's 3' end, a process known as tRNA charging, which is crucial for protein synthesis. The charged tRNA contains an anticodon that will pair with a complementary codon on the mRNA in the ribosome.
Step-by-step explanation:
An aminoacyl tRNA synthetase covalently attaches an amino acid to the cognate tRNA at its 3' end. This activation of tRNA involves the enzyme first binding and activating the amino acid with adenosine monophosphate (AMP), forming a high-energy bond, and then transferring this amino acid to the tRNA, specifically esterifying it to the 2' or 3' hydroxyl group of the terminal adenosine of the tRNA. The aminoacyl arm of the tRNA carries the amino acid, completing what is known as the tRNA charging process, readying it for protein synthesis.
The tRNA, now charged, possesses an anticodon that is complementary to a codon on the mRNA, allowing it to bring the appropriate amino acid to the ribosome during protein synthesis. These enzymes are highly specific, ensuring that each tRNA is matched with its correct amino acid.