According to carrier concept, the transport of ions across the membrane is

According to the Carrier Concept, carrier proteins are integral protein particles which have affinity for specific solutes. A solute particle combines with a carrier to form carrier solute complex. With the help of energy of ATP, the carrier protein undergoes conformational changes in such a way so as to transport the solute to the inner side and release it in the cytoplasm. Since the transport occurs against the concentration gradient and consumes energy of ATP, it is an active transport mechanism.