Final answer:
During translation elongation, EF-Tu is responsible for delivering aminoacyl-tRNA to the ribosome's A site, a process that is integral to protein synthesis and requires significant energy in the form of GTP hydrolysis.
Step-by-step explanation:
During translation elongation, amino acids are brought to the ribosome with the help of elongation factor EF-Tu. This factor binds to the aminoacyl-tRNA (aa-tRNA) along with GTP and guides it to the A site of the ribosome, based on the specific codon-anticodon pairing. Upon correct pairing, GTP is hydrolyzed to GDP and EF-Tu is released, allowing the amino acid to be positioned for peptide bond formation. This process, integral to the elongation phase of translation, is assisted by elongation factors and powered by GTP hydrolysis. The energy required for this process is significant, as protein synthesis is one of the most energy-consuming reactions in the cell.