Protein Synthesis | Rna | Ribosome
A Diagram to show the complete process of protein synthesis: ..
Eukaryotic ribosomes contain one copy of each of four different RNA species and about 80 different proteins. These components are assembled into ribosomal subunits in an ordered manner as the precursor ribosomal RNA is processed into the mature form. Pre‐rRNA processing and assembly takes place largely in the nucleolus with later stages occurring in the nucleoplasm and finally the cytoplasm. It requires numerous accessory factors, including a large number of small nucleolar ribonucleoprotein particles (snoRNPs).
The Nucleolus, Ribosomes and Protein Synthesis
Pre‐rRNA processing pathways in lower (panel A; ) and higher (panel B) eukaryotic cells. At the top, the primary transcript including the processing sites is depicted with the subsequent intermediates below. Regions corresponding to the mature rRNAs are in green; spacer regions are in brown. Light‐coloured intermediates are short‐lived and not detectable under normal conditions. Vertical and horizontal scissors indicate endonucleolytic cleavages and exonucleolytic trimming, respectively. Blue scissors in the panel B indicate that the nature of the processing step is unknown but, by analogy with yeast, is likely to be exonucleolytic. Where known, the enzyme(s) involved in a particular processing step is identified. A question mark indicates that the enzyme is still unknown.