Your friend works for a biotech company, where they have come up with a top- secret drug they hope will cure a hereditary kidney disease. He refuses to tell you anything about this drug, except to give you a peek at their data (see the figure below) regarding the kinetics of uptake of this drug into kidney cells. He thinks his data support the idea that a protein is required for the uptake of his drug; his supervisor thinks his data show that this drug simply diffuses into the cell. From what you have learned in cell biology, who is right: your friend or his supervisor? Explain your answer