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.
What the DNA Replication & Protein Synthesis Simulator shows
Step through DNA replication, transcription and translation of a short gene using real base-pairing and a genetic code table. 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 replication, transcription and translation of a short gene.
How to use the DNA Replication & Protein Synthesis Simulator
In the DNA Replication & Protein Synthesis Simulator, use the controls to change Mutate position (1-12), New base, Predicted protein length. The simulation reacts instantly.
In the DNA Replication & Protein Synthesis Simulator, pick an option such as A, T, G, C to switch modes or load an example.
In the DNA Replication & Protein Synthesis Simulator, press "Step ▶", "Apply mutation", "Apply and check my prediction", "Insert base and check" to start, reset or change what is happening.
Start with this experiment: Step through replication, transcription and translation in order. Drag any glowing handle, object or slider with your mouse or finger and the DNA Replication & Protein Synthesis Simulator responds in real time.
Change one setting at a time and watch which readout moves, then compare it with this idea: DNA replication is semiconservative: each new DNA molecule keeps one original strand and one newly built strand.
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.
The science behind it
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).
A worked example with real numbers
mRNA 5'-AUG CCU GGA-3' Protein: Met - Pro - Gly
Tips and common mistakes
Tips
- Find the start codon AUG.
- Look for stop codons UAA, UAG, UGA.
Common mistakes
- Using T in RNA.
- Reading the template instead of the coding strand.
Where this is used
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. A good first experiment in the DNA Replication & Protein Synthesis Simulator: Step through replication, transcription and translation in order. The key relation to keep an eye on: DNA -> mRNA (T becomes U) -> protein; each codon of 3 bases codes one amino acid.
For teachers: project the DNA Replication & Protein Synthesis Simulator on the board, let students predict the result, then run it together and test this: Mutate the third base of a codon and see how often it is silent. 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. The DNA Replication & Protein Synthesis Simulator is free, needs no signup or download and runs in your web browser. It is part of the Biology group of AZRS simulations.
Does the DNA Replication & Protein Synthesis Simulator work on a phone or tablet?
Yes. The DNA Replication & Protein Synthesis Simulator takes touch input as well as mouse input, so you can use its 3 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
