3. Which statement would be true of a membrane-bound protein that works in conjunction with a sodium–potassium pump during secondary active transport?
It will block a small molecule from moving across the cell membrane in response to an increase in concentration of an ion in the external environment.
It will be able to transport an ion in both directions across the cell membrane and a small molecule in one direction.
Its conformation will change when both an ion and a small molecule bind to it.
It will move a small molecule across the cell membrane in response to a build-up in concentration of the molecule in the external environment.