DNA strand cartoon

What's in your cells?

DNA model

CSIRO’s Double Helix Science Club is named after the famous shape of DNA. Learn about DNA and its role in life, and then make your own DNA model.

  • 16 October 2006 | Updated 2 November 2012

What is DNA?

Deoxyribonucleic acid (DNA) is a molecule that contains all the information to determine who you are and what you look like.

The chemical compound that makes up DNA was first discovered by Friedrich Miescher in Germany around 1869. In 1953, Francis Crick and James Watson discovered that DNA is shaped like a ladder coiled into a 'double helix' shape.

The ‘sides’ of the ladder are a linked chain of alternating sugar and phosphate molecules.

The ‘rungs’ of the ladder are attached to the sugar molecules. Each rung is made up of two chemicals called bases. There are four different bases - adenine (A), thymine (T), guanine (G) and cytosine (C) and they link together in pairs (A with T, C with G) to form a rung. The order of the bases and rungs creates a kind of code for the DNA information.

What does DNA do?

Let’s work from the large to the small.

Your body is made up of many different chemicals. An important group of chemicals is the proteins, which build your body and help it to function.

Each protein is formed from over 100 amino acids. There are 20 different types of amino acids that can be used to make proteins.

The code in the DNA ladder’s rungs is a recipe for building proteins. Tiny particles called ribosomes follow the DNA recipe to bind amino acids together and build proteins. Up to 1 000 rungs might be needed to hold the recipe for just one protein.

A group of rungs that carries the recipe for one protein is called a gene. When many genes are linked together in a DNA ‘ladder’, they form a chromosome.

Build your own DNA model

This model can be fiddly to make, but it’s well worth the effort. You'll learn some great science along the way!

You will need

  • DNA spines and rungs template (from the attached PDF document)
  • scissors
  • glue
  • string (to hang your model up with)
  • clothes pegs or paper clips.

What to do

Diagram of how to put the DNA model together.

Stick the rungs to the spines to form the DNA model.

  1. Print out the templates of the DNA rungs and spines (stiff card works better then regular paper). You'll find the link to the DNA model template to the right of this page.
  2. Photocopy or paste the templates onto light cardboard. The ideal dimensions for the model are printed on the template, so you may need to enlarge or reduce the model.
  3. Cut out spines A and B.
  4. Cut out the rungs.
  5. Fold down the tabs so that they are at right angles to the rungs (as shown in the picture).
  6. Put glue on one tab of each rung and stick them onto spine A in the numbered boxes. You can attach the rungs in any order (pointing either way). Wait for the glue to set before proceeding. You may also want to hold the rung on with a paper clip or clothes peg so it sticks well.
  7. Once the glue is dry, put glue on the other tab of each rung and stick them to the corresponding numbered position on spine B. This is the tricky part because you'll have to support both spines while the glue is drying. Once again, this is where pegs will be a BIG help.
  8. When you've completed your model, hang it from the ceiling. To complete the presentation of your molecule, cut out the Double Helix label that appears with the rungs and hang it from the bottom of the double helix.

Acknowledgements

CSIRO's Double Helix Science Club would like to acknowledge all our club members who sent in designs for a double helix model.

We would especially like to thank member Angela Smith whose design served as the inspiration that led to the construction of this model.

The Helix magazine's former editor, David Salt, fine-tuned the design. We would also like to thank Dr John Watson, a CSIRO geneticist, for his advice and help.

For more hands-on activities, join CSIRO's Double Helix Science Club.