In a hypothetical study, cells are placed in a solution of glucose in which the concentration of glucose is gradually increased. At first, the rate at which glucose enters the cells is found to increase as the concentration of the glucose solution is increased. But when the glucose concentration of the solution is increased above 10 M, the rate no longer increases. Which of the following is the likely mechanism for glucose transport into these cells? a. facilitated diffusion via a carrier protein
b. facilitated diffusion via a channel protein
c. pinocytosis
d. secondary active transport
e. hydrolysis