Final answer:
The membrane of a secretory vesicle does indeed fuse with the plasma membrane during exocytosis, releasing its contents outside the cell. This process is true and is essential for various cellular functions.
Step-by-step explanation:
The statement that the membrane of a secretory vesicle will fuse with the plasma membrane when it discharges its contents to the cell's exterior is true. This process is known as exocytosis, and it is crucial for various cellular functions, such as the removal of waste products and the release of chemical signals. During exocytosis, vesicles containing substances, such as modified and tagged proteins, move toward the plasma membrane. Upon reaching the membrane, the vesicles fuse with it, which results in the vesicle's contents being expelled to the extracellular environment. The vesicle's membrane then becomes part of the cell's plasma membrane.