3D simulation · Cells and microbes

DNA, in 3D

Name: The two-metre code
Uploaded: 2026-11-05
Description: The double helix, its four letters, how it unzips and copies itself, and how two metres of it fit inside every cell.

The double helix, its four letters, how it unzips and copies itself, and how two metres of it fit inside every cell. Not a drawing and not an AI guess: a simulation that runs the real numbers, narrated, with every moment landing on its word.

Make this video →Free to try · 11 languages · about 3 minutes

What the simulation shows

The double helix turning, labels its backbone (sugar and phosphate).
Close on the rungs: four letters, and A always pairs with T, C with G (labelled).
The two strands unzipping from one end, like a zip.
Each separated strand collecting new matching letters, so one molecule becomes two identical ones.
A short stretch (a gene) opening and being copied into a messenger strand (RNA) that floats away to be made into a protein.
Close-up: one letter changes into another, a typo (a mutation), with a flash.
Zooms out: the DNA winds on spools, coils and folds into an X-shaped chromosome.
A counter rolls up to 3.2 billion: letters in each of your cells.

The real numbers it runs on

The simulation is built on these facts, so the narration and the picture always agree:

DNA is a twisted ladder (a double helix): two backbones of sugar and phosphate, joined by rungs of four chemical letters: A, T, C and G.
The letters always pair the same way: A with T, C with G. So each strand holds all the information to rebuild the other.
To copy itself, DNA unzips and each strand collects new matching letters: two identical molecules, about 50 letters a second at each fork (thousands of forks work at once).
A gene is a stretch of DNA; to use it, the cell copies it into messenger RNA (U instead of T), which is read to build a protein.
A mutation is a change of letters, a typo; most do nothing, some cause disease, and over many generations they drive evolution.
Each human cell has about 3.2 billion letter pairs; stretched out, its DNA would be about 2 metres long, packed into a nucleus a hundredth of a millimetre wide by winding it around protein spools and folding it into chromosomes.
One full turn of the helix is about 10 letters.

The script this video was made from

“The two-metre code”: the narration of the video above. Each highlighted moment in the simulation happens on the word that names it.

Inside every one of your cells is a molecule two metres long. It's the instructions for building you.

Four letters

It's written in just four letters, and they always pair the same way: A with T, C with G.

The copy

To copy it, the cell unzips the ladder, and each half collects new partners. Two perfect copies.

Reading

To use a gene, the cell makes a messenger copy, a recipe for one protein.

Typos

Sometimes a letter changes. A single typo can change a protein.

Packed

And all of it is folded into chromosomes, 3 billion letters in a space far smaller than a grain of sand.

Make your own

Type a question, like “The two-metre code”, or your own angle on it.
ContentRoof picks this simulation, researches the facts and writes a short script, with every moment cued to a word.
A natural voice reads it in your language and the simulation plays in time with it. Change any line and it follows.
Download a vertical video for Shorts, TikTok and Reels, or use it in class.

Make this video →

Questions

Is this a real simulation or an AI-generated video?

A real simulation. DNA runs on the numbers listed above, so what you see is what actually happens, frame by frame. AI video generators guess what a scene should look like; they often get the science wrong.

Can I change what the narrator says?

Yes. Type your own question or idea and the AI writes a new script for this simulation, or edit any line yourself. Every moment of the simulation lands on the word that names it.

Which languages can it narrate in?

Eleven: English, Urdu, Hindi, Arabic, Spanish, French, Portuguese, German, Italian, Russian and Polish, with captions written properly (Urdu in Nastaliq, Arabic right to left).

Can I use it in class or post it on YouTube?

Yes. The video is yours to use in lessons, on YouTube Shorts, TikTok and Instagram Reels. The free plan makes 2 3D simulations a month; paid plans make more, in 1080p without the small mark.