Theory 04/Molecular/Molecular motors
Direction Needs Asymmetry
The claim
A molecular motor's directionality is set by the ratio of track asymmetry to thermal noise, so a symmetric track cannot produce net motion regardless of fuel.
01Mechanism
Directed motion requires a broken symmetry; thermal fluctuations randomise a symmetric walk no matter how much energy is supplied.
02Prediction
Directionality should track track asymmetry.
03Refutation
Direction independent of asymmetry would remove the ratchet.