2.8.A—Describe the processes that allow ions and other molecules to move across membranes

Describe the processes that allow ions and other molecules to move across membranes.

• Metabolic energy (such as that from ATP) is required for active transport of molecules and ions across the membrane and to establish and maintain electrochemical gradients.
  • i. Membrane proteins are necessary for active transport.
  • ii. The Na++/K pump and A TPase contribute to the maintenance of the membrane potential.