What you’ll learn to do: Describe the primary mechanisms by which cells import and export macromolecules

In addition to moving small ions and molecules through the membrane, cells also need to remove and take in larger molecules and particles. Some cells are even capable of engulfing entire unicellular microorganisms. You might have correctly hypothesized that the uptake and release of large particles by the cell requires energy. A large particle, however, cannot pass through the membrane, even with energy supplied by the cell. Instead, cells use one of two primary mechanisms that transport these large particles: endocytosis and exocytosis.