The role of the ribosome is to help mRNA and tRNA interact. It is made of two subunits and is roughly half rRNA and ribosomal proteins. The rRNA is synthesized in the nucleus while the proteins in the cytoplasm and then transported to the nucleolus. Ribosomes are globular organelles, without a membrane, constituted by proteins (ribonucleoproteins) associated with ribosomal ribonucleic acids (rRNA) from the nucleolus.