Which process describes substances leaving the cell by vesicle fusion with the plasma membrane?

Which process describes substances leaving the cell by vesicle fusion with the plasma membrane?

• A. Endocytosis
• B. Exocytosis
• C. Phagocytosis
• D. Pinocytosis

Answer: (B)

Vesicle-mediated export of materials from the cell is exocytosis. In this process, vesicles formed in the cell fuse with the plasma membrane and release their contents outside the cell, while also contributing membrane components to the surface. This is how neurons secrete neurotransmitters, glands release hormones, and cells discharge enzymes. In contrast, endocytosis brings material into the cell by infolding the plasma membrane to form vesicles; phagocytosis is a form of endocytosis that engulfs large particles, and pinocytosis involves uptake of extracellular fluid. These describe inward transport, not outward release.

Vesicle-mediated export of materials from the cell is exocytosis. In this process, vesicles formed in the cell fuse with the plasma membrane and release their contents outside the cell, while also contributing membrane components to the surface. This is how neurons secrete neurotransmitters, glands release hormones, and cells discharge enzymes.

In contrast, endocytosis brings material into the cell by infolding the plasma membrane to form vesicles; phagocytosis is a form of endocytosis that engulfs large particles, and pinocytosis involves uptake of extracellular fluid. These describe inward transport, not outward release.