Nucleolus, ribosomes and centrioles are non-membranous cell organelles. Ribosomes are large non-membranous RNA protein complexes which are necessary for protein synthesis. These attached to the outer surface ofER by ribophorins. Ribosomes are of two basic types i.e., 70S (prokaryotes, mitochondria, chloroplast) and 80S type (eukaryotic cell). Nucleolus is seen as a spherical body within the nucleus placed centrally or peripherally in close association with nucleolar organizer region. Nucleolus composed of amorphous matrix or pars amorpha, chromatin fibrils and granules. Centrioles are small granules or short rods. Two centrioles form the centrosome. Each centriole is comprised of nine sets of triplets, which arranged parallel to one another and form a cylindrical,body. Each triplet contains three microtubules.