Golgi Body

In 1898, the Italian scientist Camillo Golgi, examining nerve cells under the microscope, saw a net-like tangle of fine fibrils sitting close to the nucleus; this structure was later named the Golgi body (or Golgi apparatus) in his honour. In plant cells the same organelle typically appears broken up into many smaller units, called dictyosomes, rather than one large connected body. Structurally, the Golgi apparatus is a stack of flattened, membrane-enclosed sacs: in plant cells there are usually 10-20 such cisternae piled up, each one separated from its neighbours by a thin layer of inter-cisternal cytoplasm, and each often flat or gently curved. At the peripheral edge of the stack, the cisternae give rise to a network of interconnecting tubules (roughly 30-50 nanometres across) and to rounded or concave vesicles that pinch off from those tubules - some of these vesicles are smooth and secretory, others are coated, and the organelle also produces larger, spherical Golgi vacuoles filled with granular or amorphous material, some of which behave functionally much like lysosomes. The Golgi body itself is built up when small fragments pinch off from the ends of rough endoplasmic reticulum, forming small vesicles that then travel, join together and fuse to construct the Golgi stack. Functionally, the Golgi apparatus works as a kind of processing and packaging line: it organises a whole series of sequential steps that convert a newly synthesised protein into its finished, functional form, playing a major role in the post-translational modification of proteins and in adding sugar groups to lipids (glycosidation). Beyond this general role, the Golgi is specifically responsible for producing glycoproteins and glycolipids; transporting and stori …