One extensive membrane bound structure serves as the site of origin for protein secretions and enzymes used in other organelles. The name of this membrane bound organelles in eukaryotic is the ribosome. In the cytoplasm, ribsomal RNA (rRNA) and protein combine to form a nucleoprotein called a ribosome. The ribosome serves as the site and carries the enzymes necessary for protein synthesis. The ribosome attaches itself to m-RNA and provides the stabilizing structure to hold all substances in position as the protein is synthesized. Several ribosomes may be attached to a single RNA at any time.