Answer:
Oxidative phosphorylation is a crucial process in cellular respiration that generates adenosine triphosphate (ATP), the primary energy currency of cells. Let’s break down the statements:
Explanation:
Electron transport provides energy to pump protons into the intermembrane space.
True. During the electron transport chain (ETC), electrons are passed from one molecule to another, releasing energy. This energy is used to actively pump protons (H⁺ ions) across the inner mitochondrial membrane, creating an electrochemical gradient.
An electrochemical gradient is formed across the inner mitochondrial membrane.
True. As protons accumulate in the intermembrane space, an electrochemical gradient is established. This gradient consists of both a concentration difference (due to the buildup of protons) and an electrical potential difference (due to the positive charge of the protons).
Potassium and sodium ions form an ionic gradient across the inner mitochondrial membrane.
False. While potassium and sodium ions play essential roles in other cellular processes (such as nerve signaling), they are not directly involved in oxidative phosphorylation. The primary ions here are protons (H⁺).
Complexes I, II, III, IV actively transport protons into the intermembrane space during electron transport.
True. Complexes I, III, and IV of the ETC actively transport protons across the inner mitochondrial membrane. These complexes use the energy released during electron transfer to move protons from the matrix (inner side) to the intermembrane space (outer side).
Based on the above, the correct answer is (b) I, II, IV. These statements accurately describe the process of oxidative phosphorylation, where electron transport and chemiosmosis work together to produce ATP by utilizing the proton gradient across the inner mitochondrial membrane1234.
Summary: Oxidative phosphorylation involves electron transport, proton pumping, and the formation of an electrochemical gradient, ultimately leading to ATP synthesis.
