MicroBiology

rRNA is the prime component of the ribosomes, which are the protein synthetic factories of the cell. 18 s, 5.8 s, 28 s, and 5 s are the 4 types of rRNA molecules found in Eukaryotic ribosomes. Out of the 4 rRNA molecules 3 are synthesized in nucleolus and the other one is synthesized somewhere else. rRNA molecules are extremely abundant.as they make atleast 80% of the RNA molecules found in eukaryotic cells.


Nucleolar rRNA molecules are made on one primary transcript which is chopped in 3 mature rRNA molecules which makes the Synthesis of 3 nucleolar rRNA molecules very unusual. pre 40 s and pre 60 s ribosomal subunits are formed by the combination of rRNA molecules and the 5 s rRNA along with the ribosomal proteins in the nucleolus. These pre-subunits get exported to the nucleus where they attain maturity and take their role in the synthesis of proteins.


The rRNA molecules play vital role in the protein synthesis. Firstly the 28 s rRNA (which has a catalytic role) form the part of activity of peptidyl transferrase of 60 s subunit. Secondly, 18s rRNA plays the recognition role as it corrects the location of the mRNA and peptidyl tRNA. Thirdly, the rRNA molecules play a structural role as they fold themselves in 3D shapes which from scaffold on which ribosomal proteins assemble.