object

molecular motor

A molecular motor is a nanoscale biological machine that converts chemical energy into mechanical work.
31 related articles

Description

A molecular motor is a nanoscale biological machine that converts chemical energy—typically from ATP hydrolysis—into mechanical work. These motors are the workhorses of the cell, driving processes such as muscle contraction, intracellular transport, and the rotation of bacterial flagella. They operate in a regime where thermal fluctuations are enormous, yet they achieve directed motion with remarkable efficiency, often near 100%.

History

The concept emerged in the late 20th century, with key contributions from researchers like Paul Boyer (ATP synthase mechanism) and R. Dean Astumian, who formalized the idea of Brownian ratchets in the 1990s.

How it works

Molecular motors use a cycle of conformational changes driven by chemical reactions. For example, kinesin walks along microtubules by hydrolyzing ATP: the binding of ATP, its hydrolysis, and the release of products cause the motor's two 'feet' to alternately grip and release the track, taking discrete steps of about 8 nanometers. The energy from each ATP molecule is used to bias the motor's random thermal motion, creating a directed walk.

In practice

Molecular motors inspire synthetic nanomachines for targeted drug delivery, and they are studied to design artificial molecular pumps and actuators for nanotechnology.

Fun fact

ATP synthase, a rotary molecular motor, spins at about 100 revolutions per second, producing three ATP molecules per turn.

Concept graph →

Related articles · 31

The Piston That Waits for Emptiness
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Chemical Physics2026-08-192 minarXiv:2608.18623express
Quantum Chemistry for Hundreds of Thousands of Atoms
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Monroe: A Molecular Model with In-Context Probabilistic Inference
An interpreter gets distracted by every rustle in the hall, and a one-hour meeting stretches into two. Similarly, molecular foundation models learn the language of molecules from vast corpora, but each new conversation requires fine-tuning. Monroe changes the rules: it doesn't learn a new language but instantly finds common meaning from a few examples.
Biological Physics2026-08-012 minarXiv:2608.00654express
A Neuron Without the Extra Current
A neuron transmitting a signal is like a tiny battery that quickly discharges and recharges. For nearly 70 years, it was believed that a special "potassium valve," opening with a delay, was responsible for the recharge phase. New work claims this current is a ghost.
Statistical Mech2026-07-301 minarXiv:2607.27998express
The Walker Paradox: Why Farther Means Faster
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. The Mpemba effect remains controversial today: too many variables, hard to reproduce.
Statistical Mech2026-07-212 minarXiv:2607.18905express
Protein Courier: Why Speed Isn't Everything
Inside every cell, logistics is in full swing: tiny protein motors, like couriers, haul cargo along a network of microtubules. One of the main workhorses is kinesin, which steps using the energy of ATP (the cell's main energy currency). For a long time, researchers tried to evaluate it like a car: how much fuel it burns, how fast it gets there.
Statistical Mech2026-07-192 minarXiv:2607.17072express
Chemistry Under the Metronome
A kitchen mixer runs at a single speed, but start jabbing the button and the mixture whips up differently. Chemical reactions behave much the same way when the rates of their individual steps are not constant but pulse over time.
q-bio.QM2026-06-211 minarXiv:2606.22448express
How a cell quickly assembles DNA copies
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Mesoscale2026-06-162 minarXiv:2606.17865express
Why Left- and Right-Handed Molecules Conduct Electricity Differently
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A Sleeping Layer of Cells Remembers Which Way to Crawl
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Statistical Mech2026-05-092 minarXiv:2605.09105express
How to Stop Molecular Motors from Spinning Their Wheels
Inside every cell, life is bustling: tiny protein machines tirelessly haul cargo, read genes, and fix errors. But their work is far from perfect: they often 'spin their wheels,' take backward steps, or get stuck in futile cycles. It's like a city traffic jam where cars dart around aimlessly, burning fuel.
Quantum Physics2026-05-082 minarXiv:2605.07708express
A Quantum Motor That Runs on Its Own
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Cyanobacteria Colonies Can Weather Any Storm
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Biological Physics2026-04-231 minarXiv:2604.22024express
Mitochondria in a Traffic Jam: How Shape Decides a Neuron's Fate
Inside every neuron, there's a long, thin channel, the axon, through which signals travel from the cell body to other cells. To keep this channel working, mitochondria constantly shuttle along it. These tiny organelles produce energy and move in both directions, like cars on a narrow road.
Biological Physics2026-04-092 minarXiv:2604.08316express
How Cell Motors Set Droplet Size
Inside a cell, there are tiny liquid droplets, like oil droplets in water. They form from proteins and RNA and serve all sorts of purposes, from storing molecules to speeding up reactions. But if droplets start merging with each other, you'd end up with one big puddle, which would wreck the cell's organization.
Applied Physics2026-03-191 minarXiv:2603.18705express
Liquid Metal in a Maze
A droplet of liquid metal glides along a narrow channel like mercury from a broken thermometer. It needs no motor — the fuel is a chemical reaction with the surrounding liquid. But what happens when the droplet hits a wall? Previously, such machines were studied in open spaces, and in tight channels they behave differently.
Materials2026-03-141 minarXiv:2603.13705express
How Water Brings Membranes to Life for Green Hydrogen
A membrane for water electrolysis is like a sponge soaked with water. Inside it, hydroxide ions, particles that carry electric charge, must move freely. But exactly how they move has long been a mystery: tracking each ion in an experiment is too difficult.
Biological Physics2026-03-111 minarXiv:2603.11020express
Cilia Surfers: How Microwaves Carry Particles
Cilia are tiny hairs on cell surfaces. They beat like oars, moving fluid. In the lungs, they push dust and microbes out. But their lengths vary: in humans, they are thousandths of a millimeter; in comb jellies, several millimeters. How do such different cilia work together? Scientists built a machine that jerks fluid sharply, as if a cilium had struck. They filmed it with a high-speed camera.
Quantum Physics2026-03-051 minarXiv:2603.04708express
Tiny Sensor Detects Weak Magnetic Fields
A fridge magnet attracts a paperclip: we can feel that field with our hands. Now shrink that field by a billion times. Atoms inside our bodies emit such weak signals, and they are very hard to catch. Scientists built the sensor from special molecules that themselves behave like tiny magnets.
Biological Physics2026-03-031 minarXiv:2603.03547express
Microbial Communities: How to Find the Key Players
Microbial communities are like a noisy orchestra: thousands of instruments, and it's hard to tell who's playing the lead. In the gut, ocean, or soil, millions of bacterial species live, and scientists need to figure out which ones truly matter for human health or soil fertility. The new approach works like smart laundry sorting.
Materials2026-02-131 minarXiv:2602.12991express
A Solar Cell with a Magnetic Personality
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How Muscle Turns Fuel into Force
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Biological Physics2026-01-262 minarXiv:2601.18669express
Swimming Cells Choose Their Viscosity
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Chemical Physics2026-01-151 minarXiv:2601.10791express
Particle Physics Accelerates Molecules
In the Large Hadron Collider's detector, each proton collision leaves thousands of points — tracks of flying particles. A neural network learned to spot patterns in this scatter and predict what happened at the moment of impact.
Materials2026-01-141 minarXiv:2601.09370express
A Crystal That Smells Solvent
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Biological Physics2026-01-032 minarXiv:2601.01092express
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Chemical Physics2026-01-031 minarXiv:2601.01135express
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Chemical Physics2026-01-022 minarXiv:2601.00581express
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Biological Physics2025-12-171 minarXiv:2512.15213express
Quantum Spinning Top: How a Molecule Detects Weak Magnetic Fields
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Chemical Physics2025-12-081 minarXiv:2512.07530express
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