AP BIOLOGY

Detailed explanation-1: -When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the creation of proton-motive force (d is correct). The proton-motive force describes the force created by the tendency of hydrogen ions to move down their concentration gradient.

Detailed explanation-2: -Electrons are passed from one member of the transport chain to another in a series of redox reactions. Energy released in these reactions is captured as a proton gradient, which is then used to make ATP in a process called chemiosmosis.

Detailed explanation-3: -Intermembrane space of mitochondria This process pumps protons (H+) into the intermembrane space. The gradient created (high concentration of protons in the intermembrane space and low concentration in the matrix) causes protons to flow through ATP synthetase in the inner membrane resulting in production of ATP.

Detailed explanation-4: -This causes hydrogen ions to accumulate within the matrix space. Therefore, a concentration gradient forms in which hydrogen ions diffuse out of the matrix space by passing through ATP synthase. The current of hydrogen ions powers the catalytic action of ATP synthase, which phosphorylates ADP, producing ATP. Figure 1.

Detailed explanation-5: -The movement of protons from the mitochondrial matrix into the intermembrane space in response to electron transfer creates a protonmotive force (