[Campbell Biology P.838] Which of the following best describes the primary function of the A... | Practice Question

Which of the following best describes the primary function of the ATP-dependent proton pump in plant cell plasma membranes, as depicted in Figure 36.6 a ?

  • A: It pumps H+ into the cell, establishing a positive membrane potential inside the cell.
  • B: It pumps H+ out of the cell, contributing to a negative membrane potential inside the cell and a pH gradient.
  • C: It pumps H+ out of the cell, directly consuming ATP to transport neutral solutes.
  • D: It allows H+ to passively diffuse into the cell, maintaining turgor pressure.

Explanation

Figure 36.6 a states that plant cells use ATP-dependent proton pumps to pump H+ out of the cell. This action contributes to the membrane potential making the inside negative and establishes a pH gradient, both of which are forms of potential energy used for solute transport.