Final answer:
In the context of pinocytosis, which is a form of endocytosis, small pinocytic vesicles fuse with a larger vesicle known as an endosome for further processing within the cell.
Step-by-step explanation:
The small pinocytic vesicles you are referring to usually fuse with a larger vesicle known as an endosome. Pinocytosis is a type of endocytosis where the cell ingests extracellular fluids and dissolved substances by enclosing them in these small vesicles. These vesicles then often merge with endosomes, which can further process the contents or transport them to different parts of the cell, such as the lysosome for degradation or the plasma membrane for secretion.
Potocytosis, a variation of pinocytosis, uses caveolin to assist in the formation of even smaller vesicles called caveolae for the process of transcytosis, moving molecules across the cell. Meanwhile, during receptor-mediated endocytosis, targeted molecules are brought into the cell through clathrin-coated vesicles, which also typically fuse with endosomes after internalization.