Endocytosis and exocytosis are similar because they both allow patches of the membrane to flow from one compartment to another. According to Pearson Education, both processes require the cell to be dynamic instead of static.
Endocytosis occurs when the plasma membrane extends outward and surrounds a substance. It occurs through three different methods: phagocytosis, pinocytosis and receptor-mediated endocytosis. Phagocytosis occurs when the cell takes in a particulate, such as bacteria. Pinocytosis occurs when the cell takes in a liquid, and receptor-mediated endocytosis occurs when proteins bind to receptor cells and enter the cell through a clathrin-coated vesicle. Exocytosis, on the other hand, is endocytosis in reverse. The cell expels substances from the cell by way of a vesicle and then fuses with the membrane.
In both cases, the substances do not enter or leave the cell by passing through the membrane. Also, in both processes, the cell uses its plasma membrane to form a vesicle, which encapsulates the substances and allows them to pass into and out of the cell. Additionally, during both pinocytosis and exocytosis, liquid vesicles known as caveolae are used.
Furthermore, receptor-mediated endocytosis and exocytosis follow similar pathways, according to The Plant Cell. For example, the secretory pathways for exocytosis begin in the endoplasmic reticulum, pass through the Golgi apparatus and then end up on the outside of the cell. In the receptor-mediated endocytosis pathway, the clathrin-coated pit enters into the cell and passes into the endoplasmic reticulum. Next, it either enters the multivesicular body or passes into the Golgi apparatus.