Which statement is NOT part of the Mitchell chemiosmotic hypothesis? High-energy phosphorylated intermediates serve as phosphate donors to ADP as a result of electron transfer reactions. The use of electron transfer to power ATP synthesis requires an intact membrane. A portion of electron transport energy generates a proton-motive force, supplying the energy for ATP synthesis. ATP production is driven by a proton gradient between the matrix, which has a low proton concentration, and the intermembrane space, which has a high proton concentration.

The statement "High-energy phosphorylated intermediates serve as phosphate donors to ADP as a result of electron transfer reactions" is NOT part of the Mitchell chemiosmotic hypothesis. Peter Mitchell proposed the chemiosmotic hypothesis in 1961 to describe the process of ATP synthesis in cellular respiration and photosynthesis. This hypothesis does not involve high-energy phosphorylated intermediates; instead, it emphasizes the role of proton gradients across a membrane in driving ATP synthesis.

Extra: The chemiosmotic hypothesis revolutionized the understanding of how ATP is generated in biological systems, such as the mitochondria during cellular respiration and in chloroplasts during photosynthesis. According to this model, as electrons are transferred through a series of membrane-bound proteins known as the electron transport chain, protons (H+) are pumped across the membrane, creating a difference in proton concentration, also known as a proton gradient. This gradient creates a form of potential energy called the proton-motive force. ATP synthesis, catalyzed by the enzyme ATP synthase, is driven by the flow of protons back across the membrane, down their electrochemical gradient. This flow is analogous to water turning a turbine in a hydroelectric power station—it is the energy from the movement of protons that is harnessed to convert ADP and inorganic phosphate (Pi) into ATP. The key insight of the chemiosmotic hypothesis is that ATP is not made directly from high-energy intermediates resulting from electron transfers but instead from the energy stored in the proton gradient.