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How to Make a DNA Model out of Pipe Cleaners and Toothpicks

DNA, deoxyribonucleic acid, is the building block of life. It carries genetic information that determines what an organism looks like and how it functions. A DNA molecule is made of smaller subunits called nucleotides and resembles a twisted ladder. The sides, or backbone, of the ladder are formed by the sugar and phosphate components of the nucleotides, and the rungs are formed by four nitrogenous bases: adenine, thymine, cytosine and guanine. The arrangement of these bases along the DNA molecule determines the information contained within the organism's genes. The DNA molecule is actually two separate strands joined together in the middle by the bases, which pair in specific combinations -- adenine with thymine and cytosine with guanine.

Things You'll Need

Pipe cleaners
Toothpicks
Liquid glue

Instructions

- 1
  Build a rung of the DNA ladder by wrapping a red pipe cleaner tightly around one half of a toothpick and a green pipe cleaner around the other half. The colored pipe cleaners represent specific nucleotide bases that form a pair, such as adenine and thymine.
- 2
  Build another rung of the DNA ladder by wrapping a green pipe cleaner tightly around one half of a toothpick and a yellow pipe cleaner around the other half. These represent another pair of nucleotide bases, such as cytosine and guanine.
- 3
  Make several more of each type of rung.
- 4
  Attach the ends of the toothpicks to a straight black pipe cleaner, spacing them evenly along the length. This can be done by using a small drop of glue or wrapping the black pipe cleaner around the end of the toothpick. The black pipe cleaner represents the DNA backbone.
- 5
  Attach the other ends of the toothpicks to another straight black pipe cleaner, spacing them evenly along the length. This is the other backbone of the DNA molecule.
- 6
  Twist the DNA ladder gently to form the right-handed helical shape of the molecule. To determine whether DNA is twisted in the correct direction, hold the twisted molecule in your right hand. The backbone should curve around the center in the same direction as your fingers wrap around the DNA molecule.

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