2) Peptidyl Transfer: it is peptide bond formation steps which the amino group of peptide bond are linked to t-RNA molecule in A site and carboxyl end of polypeptide chain uncoupled from t-RNA molecule in P site. This reaction is carried out by the enzyme peptidyl transferase. Peptidyl transferase is an enzyme which is associated with 23s r-RNA of 50S-ribosomal subunit, peptide bond formation involves O to N migration and conversion of ester into amide sa given in Figure 30.11.

Figure 30.11:Structure of 70s Ribosome

TRANSLOCATION: Three things are necessary for translocation as given in Figure 30.12
(1) Deacylated RNA remove from P site
(2) Peptidyl t-RNA move from A to P site.
(3) Ribosome should move on m-RNA, one codon down, so next codon can come at A site.
Translocation step carried out by EF-G factor, During translocation accepter end of both t-RNA of A and P site are interact with peptidyl transferase centre of 23s r-RNA of 50 subunit. In translocation A and P t-RNA transfer to P and E site respectively,  as  ribosome  move three nucleotide along m-RNA chain in 5’ to 3’ direction. During translocation step GTP is converted into GDP; and uncharged t-RNA released from P site to E site (exit site) and newly formed peptidyl t-RNA from A site to P site. Elongation process is nearly same in both prokaryotes and eukaryotes.