Ribosomes -

1. It is also known as Protein factory, Engine of the cell.
2. Ribosomes are smallest cell organelles (150 x 250 Å).
3. Unit membrane less cell organelle.
4. Ribosome can be seen only through electron microscope. i.e. after electron microscopes invention, ribosomes were discovered.
5. Having negative charge due to presence of phosphate group (H₃PO₄3-).
6. Claude first observed them and called Microsome.
7. Palade coined the term Ribosome.
8. In plants Robinson and Brown first observed them in bean roots.
9. Except mammalian RBC all living cells have ribosomes.
10. Proteins in ribosomes are negatively charged.
11. Casperson and schultze, Brown and Gurdon - find out that r-RNA is synthesized in Nucleolus. Nucleolus is termed as Ribosome factory.
12. Ribosomes are universal cell organelle, present in all prokaryotes and eukaryotes.