What must happen to a protein after synthesis before it can function correctly?

After synthesis, a protein must undergo folding and modification to function correctly. Proteins are initially synthesized as linear chains of amino acids, which must fold into specific three-dimensional structures. This folding process is crucial because the protein's shape dictates its function; an incorrectly folded protein may fail to perform its biological role.

Additionally, many proteins require post-translational modifications, such as phosphorylation, glycosylation, or lipidation. These modifications can influence several aspects of the protein's behavior, including its activity, localization, and stability. Furthermore, proper folding and modifications also help proteins attain the conformation needed for correct interactions with other molecules, which are essential for their biological activities.

In contrast, other options do not reflect the necessary step for functional proteins after they are synthesized. While some proteins may require transport to specific cellular locations or interactions with other components, folding and modification are the fundamental processes that must occur for the protein to be functional.