Final answer:
The A (aminoacyl) site of the ribosome is the entry point for new charged aminoacyl tRNAs during the elongation phase of protein synthesis.
Step-by-step explanation:
The site where every new transfer RNA (tRNA) enters the ribosome during the elongation phase of protein synthesis is known as the A site, or aminoacyl site. This is where incoming charged aminoacyl tRNAs bind. The large ribosomal subunit contains three tRNA binding sites: the A (aminoacyl) site, the P (peptidyl) site, and the E (exit) site. The A site accepts the charged tRNA that is complementary to the next mRNA codon to be translated. Following the binding at the A site, a peptide bond is formed between the amino acids, the ribosome translocates moving the tRNA from the A site to the P site, and eventually to the E site where the now uncharged tRNA is released.