Bacterial Ribosomes and its type

             Ribosomes are minute cell organelles found scattered in cytoplasm. It is about 100 A in diameter . It is maded up of RNA and protein . In Eukaryotic cells, ribosomes are attached to Endoplasmic reticulum but since the bacteria lacks Endoplasmic reticulum, the ribosomes are found scattered in cytoplasm. Ribosomes are of two types called 70S and 80 S ribosome. These ribosome themselves consist of two units. The bacteria ribosome are 70S type. When the concentration of Mg++ decreases, the70S dissociate into 50S and 30S units. The 50S unit or larger unit consist of two RNA and 34 proteins and 30S unit consist of one RNA and 21 different protein. The molecular weight of bacterial ribosome is 2.5×10⁶ dalton. The bacteria RNA occur in three forms .They are 1) messanger RNA(m-RNA)  2) ribosomal RNA(r-RNA) and 3) transfer RNA(t-RNA). The function of ribosome is to synthesize protein.