Final answer:
Isoleucine, valine, and histidine have distinct structural features that affect the aminoacylation of cognate tRNA molecules. The specific recognition and binding of the correct amino acid to the appropriate tRNA molecule is determined by the structural elements present in the tRNA molecule and the matching sites of the aminoacyl-tRNA synthetase (aaRS) enzymes.
Step-by-step explanation:
Isoleucine, valine, and histidine are structurally distinct from each other in terms of their side chains. Isoleucine and valine have hydrophobic side chains, while histidine has a polar side chain with a basic nitrogen atom. These structural differences affect the aminoacylation of cognate tRNA molecules by aminoacyl-tRNA synthetases (aaRS).
The correct tRNA is recognized and aminoacylated by the aaRS based on specific recognition elements present in the tRNA molecule. These recognition elements can be localized around certain regions of the tRNA and are reflected in the 3D structure and chemical properties of the tRNA. The aaRS enzymes have specific binding sites that match the structure and properties of the cognate amino acid. This specific recognition and binding ensure that the correct amino acid is attached to the appropriate tRNA molecule during protein synthesis.