DNA holds the instructions — but it does not decide on its own when to use them. The cell's signal system chooses which gene gets copied. Let's see how. 👇
DNA is like a giant instruction library. When the cell needs something built, a signal arrives, special proteins pick the right gene, and a copier makes an RNA work-order. The RNA is used to build a protein that does the job.
🧬➜📜 Part 1 · DNA writes the RNA letters
DNA's order becomes RNA's order
The letters in the DNA decide the letters in the RNA. Each DNA letter has one partner: A→U, T→A, C→G, G→C. Press the button and watch the copier (RNA polymerase) read the DNA and build the RNA.
● DNA template (the instruction)
🖨️ RNA polymerase — ready
● RNA copy (the work-order)
Press Copy into RNA to watch DNA's letters become RNA's letters.
✗ Wrong idea
DNA says, “I want to make RNA now.” DNA is not thinking or choosing.
✓ Better idea
A signal activates proteins. Those proteins attach near a gene. Then RNA polymerase copies that gene into RNA.
🔗 Part 2 · The control chain
From a signal to a finished protein
Tap any step to learn what it does. Or press Run the signal to watch the message travel all the way down — from a need, to RNA, to a protein.
Tap a step above, or press Run the signal to watch it travel.
🎭 Part 3 · Meet the cast
A simple model to remember
Every part has one job. Tap a row to hear it.
🎚️ Part 4 · Gene switches
Genes have control regions next to them
Right next to a gene are little control parts that decide when it turns on. Tap each part to learn it.
Tap Enhancer, Promoter, or Gene above.
📖 Part 5 · The cookbook analogy
A cell is like a busy kitchen
The cookbook does not choose dinner. The kitchen situation does — and a cell works the same way.
🍳 In a kitchen
🙋 Hungry customer
▼
🧑🍳 Manager chooses the recipe
▼
🖨️ Copier makes a recipe card
▼
🍝 Cook makes the food
🧫 In the cell
📣 Signal
▼
🧑🔬 Transcription factors
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🖨️ RNA polymerase copies the gene
▼
📜 RNA ➜ 🛠️ Protein
The cookbook does not choose dinner. The kitchen situation does. 🍽️
🩹 Part 6 · Watch it happen: healing a cut
How a scrape turns genes on
DNA did not magically know there was a cut. The cell received signals, and those signals turned the right genes on. Press play to watch all 8 steps.
▶Press Play the story to begin.
“DNA did not magically know there was a cut.”
🧫 Part 7 · Same DNA, different jobs
Why a skin cell and a brain cell are different
Almost every cell in your body has the same DNA — but each type uses different genes. Tap a cell to see which genes it turns on.
💡 Part 8 · Word lab — tap a word
Every important word, in one place
Tap any word to read what it means and hear it out loud.
Tap a word above to learn it. 👆
🔊 Part 9 · Listen to the whole story
⭐ The big summary
DNA provides the code.
Signals tell the cell what it needs.
Transcription factors help choose which gene turns on.
Promoters show RNA polymerase where to start.
Enhancers help control how strongly a gene is activated.
RNA polymerase copies the gene into RNA.
RNA carries the instruction.
The protein does the work.
“The DNA is the library. The cell's signal system decides which page gets copied.”