Very tiny machines: Biological Cell Rotors
by I B Barsoum
For cells in our bodies to work they need energy. The energy cells utilize is usually stored in small units, each called ATP (Adenosine Triphosphate). When ATP is broken into ADP (Adenosine Diphosphate) by releasing one phosphate group, energy is released and used in different cell functions. So how cells make new energy units of ATPs? Cells have power houses called mitochondria where new energy is generated. To fully understand how mitochondria generate new energy please watch this video clip
The amazing part of this process is the small tiny machines on the surface of the mitochondria that use the proton gradient to generate new ATPs for the cell. This machine is called ATP synthase. If you watch back the clip , you should notice that it works as a rotor of a motor. In the clip, the action is very slow, but in real life ATP sythase spins very fast. Prof. Yoshida from Tokyo Institute of Technology tried to show its actual rotation by attaching some fluorescent filaments (of actin) to the tip of the rotor and watch it under the microscope. He found that ATP synthase rotates the actin filaments at a high speed of 8 revolutions per second. According to his calculation, it rotates with nearly perfect energy efficiency.
It is amazing to find out that the concept of an engine was invented long time ago, but at a much smaller scale and a more efficient performance. Also, the concept of generating energy from proton gradient is very similar to generating energy from waterfalls. It looks like we humans don’t invent, we discover what was invented before us, designed and built in our bodies by a much greater and wiser Mind.