Final answer:
Vesicles fuse with the Golgi apparatus for processing, the plasma membrane for exocytosis, or other organelles after being pinched off from the plasma membrane.
Step-by-step explanation:
After vesicles have pinched off from the plasma membrane, they can fuse with a few different structures depending on the vesicle's nature and function. Transport vesicles leaving the Endoplasmic Reticulum (ER) typically fuse with the Golgi apparatus on its cis face, where the cargo is processed. Afterwards, vesicles can either move to other organelles or fuse back with the plasma membrane in a process known as exocytosis.
During exocytosis, secretory vesicles merge with the plasma membrane and release their contents to the extracellular environment. In addition, during cytokinesis in animal and plant cells, Golgi vesicles play a key role in forming the plasma membrane that divides the cells in two. In summary, once vesicles have pinched off from the plasma membrane and completed their specific functions, they typically fuse with the Golgi apparatus, plasma membrane, or other organelles.