How does the plasma membrane participate in the process of exocytosis?

The role of the plasma membrane in exocytosis is crucial as it specifically involves the fusion of the plasma membrane with vesicles that contain materials intended to be expelled from the cell. During the process of exocytosis, vesicles that have formed inside the cell transport their contents to the membrane. When these vesicles reach the plasma membrane, they merge with it, effectively allowing the substances within the vesicles to be released into the extracellular space. This process is essential for various cellular functions, such as the secretion of hormones, neurotransmitters, and other important molecules.

The other options highlight different functions of the plasma membrane or cellular processes that do not directly pertain to exocytosis. While the building of vesicles happens within the cell, it is the fusion with the plasma membrane that is critical for exocytosis. Absorbing nutrients from the environment pertains to endocytosis, not exocytosis, as does controlling entry into the cell. These functions illustrate the diverse roles of membranes but do not capture the specific mechanism of exocytosis effectively.