Elongation:

At the beginning of the first round of elongation, the initiation codon (AUG) is positioned in the P site with fMet-tRNA_f^Met bound to it through codon-anticodon base pairing.  In The next codon the mRNA   is positioned   in the A site. The Elongation of the polypeptide chain occurs in three steps known as the elongation cycle which are namely aminoacyl-tRNA binding, peptide bond establishment and trans- location:

-   Aminoacyl-tRNA  binding: in this 1^st step, the corresponding  aminoacyl-tRNA for  the  second  codon  binds  to  the  A  site  via  codon-anticodon interaction.  Binding  of  the  aminoacyl-tRNA requires  elongation  factor  EF-Tu and  GTP  that  bind  as an  aminoacyl-tRNA/EF-Tu/GTP  complex. Subsequent binding, the GTP is hydrolyzed and the EF-Tu is released, now bound to GDP. Before the EF-Tu molecule can catalyze the binding of another charged tRNA to the ribosome, it must be regenerated through a process including another elongation factor, EF-Ts.  This regeneration is known as the EF-Tu-EF-Ts   replace   cycle. First,   EF-Ts   bind   to EF-Tu   and displace the GDP. Then GTP binds to the EF-Tu and displaces EF-Ts.  An EF-Tu-GTP is now prepared to take part in another round of elongation.

-   Peptide bond formation:  the 2^nd step peptide bond formation is catalyzed through peptidyl transferase.  The carboxyl  end of the amino acid bound to the tRNA in this reaction and in the P site is uncoupled  from the tRNA and becomes joined through a peptide bond to the amino set of the amino acid connect to the tRNA in the A site. A protein with peptidyl transferase activity has never been isolated.  The reason is now obvious; in E. coli at least, the peptidyl transferase activity is related with part of the 23S rRNA in the huge ribosomal subunit. Alternatively, peptidyl transferase is a ribozyme, a catalytic activity which resides in an RNA molecule.

-   Translocation:  in  the  3^rd  step,  a complex  of  elongation  factor  EF-G  (also called  translocase)  and  GTP example for  EF-G/GTP binds  to the  ribosome.  There are three concerted movements  now occur collectively known as translocation;  the deacylated tRNA moves from the P site to the E site, the dipeptidyl-tRNA in the A site shifts to the P site and the ribosome  moves along the mRNA (5' to 3') through three nucleotides to place the next codon in the A site. In during the translocation events the GTP is hydrolyzed to GDP and inorganic phosphate and EF-G is released ready to bind more GTP for another round of elongation.

After translocation, the A site is blank and ready to receive the next aminoacyltRNA. The E site and the A site cannot be occupied concurrently.  Therefore the deacylated  tRNA  is released  from  the E site  before  the next  aminoacyl-tRNA binds  to the A site  to begin  a new  round  of elongation.

Figure: The EF-Tu-EF-Ts exchange cycle.

The Elongation continues adding one amino acid to the C-terminal end of the developing polypeptide for every codon which is read with the peptidyl-tRNA moving back and forth from the P site to the A site as it grows.

Figure:  Termination of protein synthesis in prokaryotic cells.