During Active Transport, molecules move from a low concentration to an area of high concentration.
Molecules are moving the opposite direction than they would during the processes of osmosis and diffusion.
Carrier proteins in the membrane of cells are able to transport specific molecules up the concentration gradient.
Carrier proteins use energy in the form of ATP in order to carry out active transport.
Sodium ions are expelled from cells up the concentration gradient.
Potassium ions are pumped into the cell up the concentration gradient.
Source: Concepts in Biology Twelfth Edition Eldon Enger, et al.