Final answer:
The statement in question is true; an amino acid is indeed linked to the 3' OH group of a tRNA molecule during tRNA charging, a key step in protein synthesis.
Step-by-step explanation:
The statement 'On an aminoacyl-tRNA, the amino acid is linked to the 3' OH of the tRNA molecule' is true. During the process of tRNA charging, an amino acid is attached to the tRNA molecule at the 3' end. This attachment occurs at the free 3' –OH group of the terminal adenosine ribonucleotide, forming an ester bond. This critical reaction is catalyzed by an enzyme called aminoacyl tRNA synthetase, which is specific for each type of amino acid, ensuring the correct pairing of the amino acid and tRNA based on the genetic code.
Through this process, the tRNA becomes "charged" and carries the amino acid to the ribosome, where it is added to the growing polypeptide chain in a sequence dictated by the mRNA codons, with tRNA's anticodon interacting with mRNA. The anticodon arm of the tRNA is complementary to a codon on the mRNA, thereby translating the genetic code into an amino acid sequence of a protein. This intricate process is foundational to protein synthesis in cellular biology.