This is DNA

Your genes are made of DNA. DNA is a group of atoms, called a molecule, that contains your genetic information. DNA is shaped like a twisted ladder and the ladder's rungs are chemicals called bases - A, T, G and C (adenine, thymine, guanine and cytosine). Its frame is made of sugar and phosphate.

Click here to read a transcript of a video from this exhibit station.

DNA's a copycat

DNA makes new DNA by unwinding and unzipping into two strands, with each serving as a template for a new strand. Helper proteins, called enzymes, assist during DNA copying. Starting at the end of one strand, enzymes add new rungs (bases)-Ts fasten to As, and Cs fasten to Gs. Meanwhile, other enzymes add new rungs to the other strand. The result: two DNA ladders where there used to be one.

Amazing Facts

• If the DNA in just one of your cells unwound, it would stretch about six feet.



• Laid end to end, the unwound DNA in all your cells would stretch to the sun and back about 400 times.



• Strands of DNA are so tiny, you could fit about five million strands through the eye of a needle.



• Your genome contains about 3 billion "letters."

Videos

Double Helix (2:26)
Windows Media - 4.22mb | QuickTime - 4.98mb | Real Media - 5.32mb

Double Helix Video Transcript:

Hello! My name is Eric Lander.

What you see before you is the DNA double helix. It's the secret of you, the secret of me, and actually the secret of all life on this planet. The DNA double helix is made up of genes which are sort of a recipe for who you are. The only problem is, that recipe is written in a secret code. It took a very long time to figure out how to read that code - but now we have it!!

To read the code you have to learn a new alphabet. Instead of your ABCs, you have to learn your As, Ts, Cs and Gs. The letters stand for chemicals called bases. A stands for adenine, T for thymine, C for cytosine, and G for guanine.

The secret is that As always pair up with Ts and Cs always pair up with Gs on the two sides of the double helix.

The neat thing about the DNA double helix is that it can make a copy of itself. That's how genes can be passed on from parents to their children.

To make a copy of itself, the DNA unwinds and splits down the middle. Each strand of the double helix becomes a template for a new partner strand. With the help of special proteins called enzymes, each half rebuilds and restores the missing half. Remembers As always pair up with Ts and Cs always pair up with Gs.

Now where we have just one double helix we've got two identical copies of the double helix. That's how the code of life replicates itself.

DNA double helix is the key to the mystery of lifeIt holds the instructions for how we live and breathe, all written out in a four letter code.

It's really pretty simple when you think about it but it is the secret of life.