Energy for primary active transport comes from ATP molecules. ATP is produced by the mitochondria. e.g. Na+/K+ ATPases are archetypal primary active transporters and they transport 3 Na+ ions out of cells and 2 K+ ions into cells by hydrolyzing one molecule of ATP. Energy for secondary active transport is stored in an established concentration gradient of ions across the cell membrane and drives transport with the tendency of ions to move from an area of high concentration to an area of lower concentration. e.g. Na+/glucose secondary transporters use the Na+ gradient (higher outside cells than inside) established by Na+/K+ ATPases to transport a molecule of glucose along with a sodium ion into cells. Solution Energy for primary active transport comes from ATP molecules. ATP is produced by the mitochondria. e.g. Na+/K+ ATPases are archetypal primary active transporters and they transport 3 Na+ ions out of cells and 2 K+ ions into cells by hydrolyzing one molecule of ATP. Energy for secondary active transport is stored in an established concentration gradient of ions across the cell membrane and drives transport with the tendency of ions to move from an area of high concentration to an area of lower concentration. e.g. Na+/glucose secondary transporters use the Na+ gradient (higher outside cells than inside) established by Na+/K+ ATPases to transport a molecule of glucose along with a sodium ion into cells..