Hot water sometimes freezes faster than cold. Ice forms more quickly from boiling water. This paradox, discovered by schoolboy Erasto Mpemba, long puzzled physicists. It turns out: the farther a system is from equilibrium, the faster it relaxes back to it.
A similar paradox has been found inside living cells. It is demonstrated by the walking protein kinesin — a molecular courier. It steps along microtubules, delivering vital cargo. Each step, 8 nanometers long, burns one molecule of ATP — the cell's fuel.
Researchers built a six-state model of the motor. They tested its behavior with and without fuel. Even at rest, Stochastic modeling obeys the Mpemba effect: starting from a “hot” state speeds up the transition to a steady walking rhythm. The secret lies in how entropy (a measure of disorder) changes along the path to equilibrium. From chaos, the system finds the main road to calm faster. Adding fuel or load didn't break the pattern — they merely shifted the conditions for the speedup. Interestingly, the walking speed itself betrays the anomaly. It can be measured in the lab.
So, in the nanoworld, the shortest path isn't always the quickest. A motor that starts farther away often reaches its goal sooner — just as hot water turns to ice faster than cold.
Kinesin's step is 8 nanometers. That distance is enough to keep it on track: the microtubule is marked like a trail with repeating protein blocks.