AP BIOLOGY

Detailed explanation-1: -The proton gradient generated by proton pumping during the electron transport chain is a stored form of energy. When protons flow back down their concentration gradient (from the intermembrane space to the matrix), their only route is through ATP synthase, an enzyme embedded in the inner mitochondrial membrane.

Detailed explanation-2: -The movement of protons through ATP synthases occurs from the inner membrane to the matrix. The electron transport chain creates a gradient for the protons to move across the membrane and drive the synthesis of ATP. This process not only occurs in the Krebs cycle and glycolysis but in photosynthesis as well.

Detailed explanation-3: -Answer and Explanation: The movement of protons (H+) down a concentration gradient through ATP synthase occurs from the inter-membrane space of the mitochondria (where protons accumulate) to the mitochondria matrix, passing through ATP synthase located on the mitochondria’s inner membrane.

Detailed explanation-4: -The energy used in the electron transport chain pumps protons across the inner mitochondrial membrane from the inner matrix to the intermembrane space, producing a strong hydrogen concentration gradient. This process was called chemiosmosis by its discover, Peter Mitchell.

Detailed explanation-5: -Hydrogen ions in the matrix space can only pass through the inner mitochondrial membrane through a membrane protein called ATP synthase. As protons move through ATP synthase, ADP is turned into ATP. The production of ATP using the process of chemiosmosis in mitochondria is called oxidative phosphorylation.