2.5.B—Describe the mechanisms that organisms use to transport large molecules across the plasma membrane

Describe the mechanisms that organisms use to transport large molecules across the plasma membrane.

• The processes of endocytosis and exocytosis require energy to move large substances or large amounts of substances into and out of cells.
  • i. In endocytosis, the cell takes in large molecules and particulate matter by folding the plasma membrane in on itself and forming new (small) vesicles that engulf material from the external environment.
  • ii. In exocytosis, internal vesicles release material from cells by fusing with the plasma membrane and secreting large molecules from the cell.