Fearfully and Wonderfully Made

ATP synthase is not simple. Comprising thousands of amino acid building blocks in about 10 kinds of protein chains, its intricate structure carefully directs a flow of acid particles, beginning from outside the cell, through deep channels in the machine’s organization, into the cell’s interior. Somehow, like the cascade of water over a hydroelectric dam that turns a turbine, the flow of acid through the channels rotates a central camshaft. The cams push against multiple discrete areas of a stationary region of the synthase, distorting their shapes. The distortion forces together two bound feed-chemicals, ADP and phosphate, provoking them to react to yield the energy-rich-yet-stable molecule ATP. As the camshaft completes a turn, the ATP is released into the cell, and the machine begins another cycle. Incredibly, the many copies of the machine in each person produce about 150 pounds of ATP molecules every day, but each is used rapidly as energy — in effect, recharging each cell like a reusable battery.