The last step in protein synthesis is called termination. During this stage, the newly formed polypeptide chain is released from the ribosome once a stop codon on the mRNA is reached.
In more detail, protein synthesis occurs in two main phases: transcription and translation. After a protein is assembled by ribosomes, it undergoes this termination step. When the ribosome encounters one of the three stop codons (UAA, UAG, or UGA) on the mRNA, there is no corresponding tRNA to match these codons. Instead, a release factor protein binds to the ribosome, prompting it to cut the bond between the last tRNA and the completed polypeptide chain.
Following termination, the polypeptide chain will fold into a specific three-dimensional shape to become a functional protein. This final step is crucial because the proper folding is essential for the protein to perform its roles in the cell.