Where does the rRNA function in cells?

Molecules of rRNA are synthesized and processed in the nucleolus, which is a dense area inside the nucleus and has the genes that encode rRNA. The nucleolus is also the site of ribosome assembly. rRNA functions within the ribosome of cells. The rRNA molecules regulate the catalytic steps of protein synthesis, such as the joining together of amino acids, to generate a protein molecule. For this reason, rRNA is also known as a ribozyme or catalytic RNA. In the nucleolus, the large and small rRNA subunits combine ribosomal proteins to create the large and small subunits of the ribosome. Ribosomal proteins are synthesized in the cytoplasm and transported to the nucleus. The subunits are then transported back to the cytoplasm for final assembly.