Home▸Biophysics▸DNA Mechanics: Persistence Length and the Worm-Like Chain

🧬 DNA Mechanics: Persistence Length and the Worm-Like Chain

Interactive 3D DNA strand rendered as a worm-like chain where users adjust persistence length and applied tension to see the molecule flex between a rigid rod and a floppy coil.

Biophysics2DAdvanced60 FPS

A single DNA molecule is anchored at one end and pulled from the other, rendered as a twisted double-helix strand whose bending statistics follow the worm-like chain model of polymer physics.

🔬 What It Demonstrates

Persistence length sets how quickly the strand's direction randomizes along its contour; applied tension biases each segment toward the pulling axis, matching the Marko–Siggia force–extension law used to interpret real optical-tweezers experiments.

🎮 How to Use

Drag persistence length from floppy to stiff, pull harder with the tension slider, and change the contour length to see the chain shift between a random coil and a taut rod. Toggle thermal wiggling to freeze a single conformation.

💡 Did You Know?

B-form DNA has a persistence length of roughly 50nm — about 150 base pairs — which is why short DNA fragments look like stiff rods while genome-scale DNA folds into a floppy coil.

⚙ Under the hood

Interactive 3D DNA strand rendered as a worm-like chain where users adjust persistence length and applied tension to see the molecule flex between a rigid rod and a floppy coil.

dna-mechanicspersistence-lengthworm-like-chainpolymer-physicsbiophysicsdna

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install