Ribosomes are also called Palade's granules or engine of the cell or protein factories. The ribosomes were discovered and named by Palade. Ribosomes are smallest and most abundant cytoplasmic organelle.Ribosomes are made up of protein and RNA in about equal amounts. Ribosomal RNA contribute about 80% of cell RNA. Ribosomes are attached to the RER through glycoproteins known as ribophorins. They are about 20nm in diameter. the mass of ribosomes is expressed in Svedberg units.
They are of two types:
1.Cytoplasmic ribosomes: It is 70s type in prokaryotic and 80s type in eukaryotic cell.
2.Organelle ribosomes: They are 70s, 55s, 73s, 67s, 60s types and found in organelle of eukaryotic cells like plastids, mitochondria and nucleus.
No comments:
Post a Comment