How to Build a Double Helix DNA Nucleotide Structure
Nucleotides in DNA consist of a deoxyribose sugar attached to a phosphate group and one of four nitrogenous bases: adenine, guanine, cytosine and thymine. The phosphate groups allow the deoxyriboses in each nucleotide to be linked together forming long chains. In double-stranded DNA, two DNA strands are hydrogen bonded to each other along their bases. These bases have specific complementary pairs, with adenine complemented by thymine, and cytosine complemented by guanine. Building a double helix DNA nucleotide structure requires representation of the phosphate, deoxyribose and bases in two complementary strands of DNA.
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Things You'll Need
- Floral wire
- Craft wire
- Floral stand
- Modeling clay (black, yellow, red, purple, green and yellow)
Instructions
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1
Create a ladder structure using two pieces of floral wire as the sides of the ladder and 2-inch pieces of craft wire as the rungs of the ladders. Space the rungs two inches apart and leave at least two inches free on one end of the ladder. This provides the structural framework for the model.
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2
Cover the joints of the ladder where the craft wire attaches to the floral wire with black modeling clay to represent deoxyribose. Mold the black clay into a spherical shape around the joints.
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3
Mold the yellow clay into small balls around the floral wire between the balls of black clay. These small balls of yellow clay should be half way between the black balls. The yellow clay represents the phosphate groups that join the deoxyribose of each nucleotide together.
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4
Roll one of the various colors (red, purple, green and yellow) of clay representing the bases in DNA on one side of the craft wire adjacent to the black clay representing deoxyribose. Continue adding a color to the side of each rung of the ladder. The color sequence may be varied.
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5
Mold a corresponding color for each base on the other side of the ladder rungs. With red representing adenine, blue for thymine, yellow for cytosine, and purple for guanine, the correct combination of colors is red to blue and yellow to purple. This corresponds to the base pairing between two strands of DNA.
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6
Twist the ladder counterclockwise to give the DNA model its characteristic helical shape. The twist should allow one complete rotation of the model about every 10 base pairs.
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7
Insert the free ends of the floral wire into floral foam.
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