Tell us how amino acids are attached to t-RNA molecules.

The transport RNA molecule can be conventionally represented as a chain folded in the form of a three-leaf clover with a stem oriented opposite the “middle leaf” – a tRNA loop carrying an anticodon. The region corresponding to the “stem” contains a single, free cytosine-cytosine-adenine nucleotide sequence bearing a free hydroxyl group —OH. It is to this end that the amino acid is attached with the help of special enzymes – aminoacyl-tRNA synthetases. This is a group of enzymes, within which there is a specialization: certain varieties of this enzyme attach amino acids strictly to certain tRNAs. The attachment of the amino acid occurs in accordance with the tRNA “middle leaf” anticodon.