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DNA model

What is DNA?

DNA or Deoxyribonucleic acid is a molecule which contains all the information the body needs o determine what you will look like and the kind of person you will be. Deoxyribonucleic acid was first identified by the German, Friedrich Miescher in about 1869. It wasn’t till 1953 that Francis Crick and James Watson discovered that DNA was shaped like a ladder, which is coiled into a ‘double helix’ shape. A linked chain of sugar and phosphate molecules make up the ‘sides’ of the ladder. The ‘rungs’ of the ladder are attached to the sugar molecules on the ‘side’ of the ladder. Two chemicals make up each of the ‘rungs’, these chemicals are called bases. Adenine (A), thymine (T), guanine (G) and cytosine (C) make up the four different types of bases, these chemicals are paired together (A with T and C with G) to form a ‘rung’ on the ladder. The DNA information is held within this order of the bases and rungs in order to form a code.

What Does DNA Do?

All living things contain DNA

The human body contains many different chemicals, one of the most important groups of chemicals is proteins, and proteins build the body and help the body to function. It takes over 100 amino acids to make up a protein and there are 20 different types of amino acids which the body used to make up proteins. The rungs of the DNA ladder contain the information required for the building of proteins. Microscopic particles called ribosomes bind amino acids together to build proteins using the information provided by the DNA.

A single protein may need the information contained in over 1000 rungs in order to establish. A group of rungs required to produce a protein is known as a gene.

Genes linked together on the DNA ‘ladder’ are known as a chromesome.

Build your own DNA ladder model.

Building your own DNA ladder will help you to understand how all the information fits together.

To complete the task you will need the following-

  • Stiff card
  • Scissors
  • Glue
  • String or cord (to hang the model up with)
  • Clothes pegs or paper clips.

How to make the DNA ladder-


  1. Using stiff card, print out the DNA rungs and spines using the DNA model template.
  2. Photocopy or paste the templates on to light card. (Enlarge or reduce to suit needs).
  3. Cut out spines A and B.
  4. Cut out rungs
  5. Next glue the rungs to the spines to form the DNA ladder as follows-
  7. 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 dry. Hold the rung on with a paper clip or clothes peg so it sticks well.

Cut out the double helix label which appears with the rungs and hang it from the bottom of the double helix.

Once the model is complete it can be hung from the ceiling.

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.



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2017 "Научная ярмарка".