polypeptide chain elongation
In the process of elongation, a charged t-RNA binds to the ribosome and a peptide bond is formed between the growing (nascent) polypeptide chain and the amino acid on the aminoacyl-tRNA. The codon sequence of the mRNA determines which amino acyl-tRNA is bind to the ribosome.
The carboxyl (COOH) group of the amino acid in A site and the amino groups (NH2) of the amino acid attached to the tRNA in the P site.
To see a cartoon of polypeptide chain elongation click here: chain elongation