(53)
3. Beskrive at rRNA'er udgør fundamentale bestandele af ribosomet, samt angive deres distribuering
 Devlin, s.243,fig.6.7

 

rRNA is the fundamental component of a ribosome. It was though that the catalytic part of the ribosome is a protein, since they are enzymes. The active site of the ribosome is located on the large subunit, and there are no protein functional groups close enough to catalyse the peptide bond formation, so it must be a part of the RNA chain that serves as a catalyst.

Therefore, the key sites in ribosomes are composed almost entirely of RNA.
The protein component serves as a structural scaffolding and reassembly.

Ribosomes are made of two subunits, a large and a small one. Each subunit includes an RNA core, folded into a specific 3-dimensional structure, upon which proteins are positioned through protein-RNA and protein-protein interactions.  

There is a difference in the structure of ribosomes in prokaryotes and eukaryotes.
 

Prokaryote ribosomes (70S):  

The large subunit is called 50S and is made up of:

The small subunit is called 30S and contains:

Eukaryote ribosomes (80S) are bigger and more components:

The large subunit is called 60S and contains:

The small subunit, 40S:

 

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