DNA Replication & Protein Synthesis Simulator
Step through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect.
Press Step to move through replication, transcription and translation of a short gene, then introduce a point mutation and see whether it is silent, missense or nonsense.
About the DNA Replication & Protein Synthesis Simulator
Free dna replication & protein synthesis simulator. Step through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect. Drag, change the sliders and see the result live. No sign-up, works on phone and computer. Built for biology, the dna replication & protein synthesis simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Step through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table, then introduce a mutation and classify its effect. Use it to explore biology ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the DNA Replication & Protein Synthesis Simulator
- Use the controls to change Mutate position (1-12), New base, Predicted protein length. The simulation reacts instantly.
- Pick an option such as A, T, G, C to switch modes or load an example.
- Press "Step ▶", "Reset to defaults", "Apply mutation", "Apply and check my prediction" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Step through replication, transcription and translation in order.
- Mutate the third base of a codon and see how often it is silent.
- Mutate a base to create an early stop codon and watch the protein get cut short.
- Predict whether your chosen mutation will be silent, missense or nonsense, then check.
Key ideas you can learn
- DNA replication is semiconservative: each new DNA molecule keeps one original strand and one newly built strand.
- Transcription copies a DNA template strand into mRNA, pairing A with U instead of A with T.
- Translation reads mRNA three bases (one codon) at a time and matches each codon to an amino acid using the genetic code, until a stop codon is reached.
- A point mutation can be silent (same amino acid), missense (different amino acid) or nonsense (creates an early stop codon).
Where this is used in the real world
Genetic counselors and cancer researchers classify real mutations this same way - silent, missense or nonsense - to judge how serious a DNA change is likely to be.
Who is this simulation for?
Biology students and teachers who want to explore living systems, populations and genetics interactively and safely.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why is DNA replication called semiconservative?
Each of the two resulting DNA molecules contains one strand from the original molecule and one newly synthesized strand.
Why don't all mutations change the protein?
The genetic code is redundant - several different codons can code for the same amino acid, so some base changes are silent.
Is the DNA Replication & Protein Synthesis Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the DNA Replication & Protein Synthesis Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.