Molecule binds to receptors in the channel of the carrier protein on the outside of the cell, ATP binds to the carrier protein on the inside of the cell and is hydrolysed into ADP and phosphate, binding of phosphate molecule to the carrier protein causes the protein to change shape which opens up the inside of the cell, molecule is released to inside of the cell, phosphate molecule is released from the carrier protein and recombines with ADP to form ATP, carrier protein returns to original shape