The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the a. oxidation of glucose and other organic compounds. b. flow of electrons down the electron transport chain. c. H+ concentration gradient across the membrane holding ATP synthase. d. transfer of phosphate to ADP.

Verified step by step guidance

1. Identify the process involved: The question refers to ATP synthesis by ATP synthase during oxidative phosphorylation, which is a key part of cellular respiration.
2. Understand the role of ATP synthase: ATP synthase is an enzyme that synthesizes ATP using energy from a proton (H+) gradient across a membrane.
3. Analyze the options: Option (c) mentions the 'H+ concentration gradient across the membrane holding ATP synthase', which directly relates to the function of ATP synthase.
4. Recall the mechanism: During oxidative phosphorylation, electrons travel down the electron transport chain, creating a proton gradient across the mitochondrial membrane. This gradient drives the ATP synthase to synthesize ATP.

Key Concepts

ATP Synthase

ATP synthase is an enzyme complex located in the inner mitochondrial membrane that synthesizes adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate (Pi). It utilizes the energy derived from a proton (H+) gradient created during oxidative phosphorylation, allowing protons to flow back into the mitochondrial matrix, driving the conversion of ADP to ATP.

Electron Transport Chain (ETC)

The electron transport chain is a series of protein complexes and other molecules embedded in the inner mitochondrial membrane that transfer electrons from electron donors like NADH and FADH2 to electron acceptors. This process releases energy, which is used to pump protons across the membrane, creating a proton gradient essential for ATP synthesis.

Proton Gradient

A proton gradient refers to the difference in proton concentration across a membrane, which is crucial for ATP production during oxidative phosphorylation. The gradient is established by the electron transport chain, and the flow of protons back into the mitochondrial matrix through ATP synthase harnesses this energy to convert ADP into ATP, the primary energy currency of the cell.