Which of the following experimental results does not support Mitchell's chemiosmosis theory?

• Electron transport in isolated mitochondria was shown to result in acidification of the medium
• Addition of dinitrophenol to isolated mitochondria was shown to inhibit electron transport, but had no effect on ATP synthesis
• Addition of dinitrophenol to isolated mitochondria during electron transport was shown to inhibit acidification of the medium
• An artificial proton gradient across the inner mitochondrial membrane drives ATP synthesis in the absence of electron transport