The main function of active transport is to pump molecules and ions across membranes against their concentration gradients. Active transport is an energy-requiring process that can transfer substances into, out of, and between cells. It moves substances from a low concentration to a region of higher concentration. Another function of active transport is assisting in maintaining the cell’s homeostatic regulation and cell function. Maintaining homeostasis for the cell is important for its function because conditions consistently change inside and outside the cell.