[Campbell Biology P.188] Which statement best describes the primary difference between exocy... | Practice Question

Which statement best describes the primary difference between exocytosis and endocytosis?

  • A: Exocytosis releases substances from the cell, while endocytosis takes substances into the cell.
  • B: Both processes primarily transport small molecules like ions and water across the membrane.
  • C: Both exocytosis and endocytosis always require ATP directly.
  • D: Exocytosis involves forming new vesicles from the plasma membrane, while endocytosis involves vesicle fusion with the plasma membrane.

Explanation

Exocytosis is the process by which cells secrete molecules by fusing vesicles with the plasma membrane, releasing contents outside the cell. Endocytosis is the reverse, where the cell takes in molecules by forming new vesicles that pinch inward from the plasma membrane.