AMP-PNP is a non-hydrolyzable ATP analog that cannot be metabolized by cells. Taurocholate is a bile acid that helps emulsify fats. When taurocholate is added to hepatocyte cell culture, it accumulates in those cells. The graph below shows the rate of cellular accumulation of the drug taurocholate in the presence of either no ATP, ATP, or AMP-PNP. Based on this data, describe the mechanism by which taurocholate enters the cell. Justify your answer.