Which active transport process involves the expending of energy to package large substances into secretory vesicles?

Exocytosis is an active transport process that involves the expending of energy to package large substances into secretory vesicles. This process is essential for transporting materials out of a cell, particularly when those materials are too large to pass through the cell membrane directly.

During exocytosis, substances that the cell needs to release—such as hormones, neurotransmitters, or waste products—are enclosed in vesicles formed from the cell membrane. The vesicles then fuse with the cell membrane, allowing the contents to be released into the extracellular environment. This energy-dependent mechanism ensures that the cell can regulate its internal environment and communicate with other cells effectively.

The other processes, while they involve movement of substances across membranes, do not specifically pertain to the packaging and release of large substances in the same manner as exocytosis. For instance, endocytosis involves taking substances into the cell, while phagocytosis and pinocytosis are specific types of endocytosis that involve the ingestion of larger particles and smaller liquids, respectively.