TYPES OF RIBOSOMES

FREE RIBOSOMES: Free ribosomes are found in the cytoplasm of the cell. They occur as single ribosomes or as groups called polysomes or polyribosomes. Synthesize those proteins that are important for the formation of cell structure units. BOUND RIBOSOMES: Bound ribosomes are present in the membrane of RER. The ribosomes produce proteins packed in vesicles, are exported to the exterior of the cell. NON- CYTOPLASMIC RIBOSOMES: Ribosomes are also located in the mitochondria and the chloroplast of eukaryotic cell. These ribosomes are smaller in size and resemble prokaryotic ribosomes. (70S) FUNCTION: The primary function of ribosomes is the synthesis of proteins. GOLGI APPARATUS; DISCOVERY: An italian neurologist (physician) Camillo Golgi in 1898 discovered Golgi appratus. OCCURRENCE AND DISTRIBUTION: The Golgi apparatus occurrs in all cells expect the prokaryotic cells (mycoplasmas, bacteria and blue-green algae) and eukaryotic cells of certain