Question

q3.9. for which of the following is potential energy decreasing? (hint: click here to see an overview of the etc.) protons moving from the mitochondrial matrix to the intermembrane space adp gaining a phosphate group to become a molecule of atp two protons being moved closer toward each other electrons moving from complex iv to o₂

Explanation:

1. Protons moving from mitochondrial matrix to inter - membrane space: This requires energy input as it builds a proton gradient, increasing potential energy.
2. ADP gaining a phosphate group to become ATP: Energy is stored in the high - energy phosphate bond of ATP, so potential energy increases.
3. Two protons being moved closer: Since like charges repel, moving them closer requires work and increases potential energy.
4. Electrons moving from Complex IV to O₂ in the electron transport chain (ETC): In the ETC, electrons flow from higher - energy carriers to lower - energy acceptors. Oxygen is the final electron acceptor and has a lower energy state compared to Complex IV. As electrons move from Complex IV to O₂, they release energy and their potential energy decreases.

Answer:

Electrons moving from Complex IV to O₂