Vesicles are membrane-enclosed structures that form inside cells during endocytosis, which is the process where the plasma membrane forms inward pouches to internalize extracellular material. Vesicles serve to transport materials within the cell, such as carrying raw materials processed by the Golgi complex to their final destinations for secretion or transport. The Golgi complex processes raw materials into finished products and sorts and directs where the finished products will go inside the cell.