Physics

Quantum Tunneling

Quantum tunneling occurs when a particle traverses an energy barrier that classical physics says it cannot cross. This is not a theoretical curiosity — it is essential to life. Enzyme catalysis, the engine of all metabolism, depends on hydrogen atoms tunneling through energy barriers to accelerate reaction rates by factors of thousands. Without tunneling, the biochemistry of life would be too slow to sustain it. In mitochondrial Complex I, electron tunneling across chains of iron-sulfur clusters drives the proton pumping that generates ATP.