At this point we have a polypeptide chain composed of amino acids. However, we do NOT yet have a functional protein. As mentioned before, proteins get their functions from their structure. Right now all we have is a chain of amino acids. To get into their correct structure, the polypeptide chain goes through a process called protein folding.

As the polypeptide chain leaves the ribosome, it begins to fold by attractions and repulsions between parts of the chain. Proteins called chaperone proteins assist in this process. Enzymes check the folding protein for mistakes and correct them.

If all goes well, we now have a fully functional protein. Below is an illustration for protein synthesis.