Flexi Says: The nucleolus is a round, membrane-less granular structure within the nucleus of a cell, and composed of protein and RNA. The nucleolus produces ribosomes, the organelles that manufacture proteins in the cell. Extra ribosomal functions assigned to the nucleolus include the involvement in cell cycle and cell proliferation control, stress sensing and tumor surveillance pathways, apoptosis, telomere formation, transfer RNA modifications, viral lifecycle, etc.
