Still, firm evidence was needed. This was recently achieved by Yoshida, who attached a very long (1-3 micrometers) actin filament with a fluorescent marker to the upper motor (10 nanometer diameter) ...

The gradient created by this drives hydrogen back through the membrane, through ATP synthase. As this happens, the enzymatic activity of ATP synthase synthesiszes ATP from ADP. Mitochondria are ...

Again, the structure betrays the mechanism — in this case not a rotary motor but, even more surprisingly ... protein machinery as the ATP synthase. There are a few possible abiotic mechanisms ...