In exocytosis, a cell expels molecules and other contents that are too large to pass through the cell membrane structure. This discharge is accompanied by the fusion of the vesicular membrane and the plasma membrane. This process is carried out in three ways that separately involve the molecular constituents like endosomes, lysosomes, exosomes, neurotransmitters, etc.
In endocytosis, the body cells ingest various molecules such as proteins, polar molecules, and other substances, through their hydrophobic plasma membrane. This process is carried out by many eukaryotic cells to ingest food particles by surrounding them, and in this case, the plasma membrane is extended outwards. The basic mechanism of both the processes of exocytosis and endocytosis, is more or less the same. Vesicles are the structures used for the transportation of molecules. They are also used for storage and transportation of food. Also, many bacteria and pathogens may enter the body by this process. These structures may have a completely different internal composition as compared to that of the body cells.