Final answer:
Exocytosis affects membrane flow by increasing the plasma membrane surface area as materials are expelled and vesicle membranes are incorporated into the cell membrane.
Step-by-step explanation:
The effect of exocytosis in terms of membrane flow is the increase of the cellular membrane surface area as material is expelled from the cell. During exocytosis, secretory vesicles containing substances such as waste, proteins, or neurotransmitters, fuse with the plasma membrane. This fusion results in the addition of the vesicle membrane to the plasma membrane, followed by the release of the vesicle's contents into the extracellular space. The process not only disposes of cellular waste and releases important cellular products but also has a role in replenishing and recycling parts of the plasma membrane.