Golgi apparatus

The Golgi apparatus which is a system of flattened membrane-bound sacs is the sorting and processing center of the cell. From the RER Membrane  vesicles, containing membrane  and  secretory  proteins,  fuse  with  the  Golgi  apparatus  and  release their contents into it. Further post-translational modifications to these proteins take place on transit through the Golgi apparatus, and they are then sorted and packaged into various vesicles. From the Golgi apparatus these vesicles bud off and are transported  through the cytosol, fusing either with the plasma membrane  to release their contents into the extracellular space (a procedure known as exocytosis;)  or  with  other  internal organelles (for example: lysosomes) eventually.