Final answer:
The step not part of the elongation phase is the binding of initiator tRNA to the AUG start codon; this step occurs during the initiation phase of translation, not elongation.
Step-by-step explanation:
The step in translation that is not part of the elongation phase is A. Binding of initiator tRNA to AUG start codon. This step is actually part of the initiation phase, where the initiator tRNA carrying methionine recognizes the AUG start codon on the mRNA and binds to the P site of the ribosome.
The elongation phase involves charged tRNAs sequentially entering the ribosome at the A site, the formation of peptide bonds between amino acids, and subsequent translocation of the ribosome along the mRNA by three bases in the 3' direction.
During elongation, an uncharged tRNA is indeed ejected from the E site (B), ribosomes move three bases towards the 3' end of the mRNA (C), and peptide bond formation occurs (D).