Build a DNA Model

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Are you interested in building your very own DNA model- the original building blocks of life? Then consider getting your inner artist out and create a model of DNA from polymer clay or wire and beads for a project that will be sure to win any science fair.

Steps

Building a Model out of Clay

  1. Get your supplies. To make a DNA model out of clay, you will need to first purchase your clay of choice. A polymer clay in at least six colors will do the trick, in addition to any tools you may want to use to shape the clay (such as a plastic knife or rolling pin).
    • If you plan on exhibiting your model of DNA when you finish, prepare a base for it to sit on. This might be a small wooden board with a dowel running through the center for the DNA strand to be attached to.
    • You will need to bake the polymer clay when you finish shaping it, so make sure you have a working oven available too.
    • You may choose to use a flexible wire to give added support to your DNA model.
  2. Create two long strands to represent the double helix. Choose one of your polymer clay colors, and roll it out into pieces about one foot long and ½ an inch thick. These will form the sides of the strand of DNA, so make sure they are sturdy enough that other pieces can be attached without them falling apart.
    • To add extra support to your structure, you can wrap the clay around two long pieces of flexible wire.
    • You can freely alter the size of your DNA model strand to meet your personal preferences. To create a smaller DNA model, simply reduce the size of these double helix strands.
  3. Add the sugar and phosphate groups. The double helix strands of DNA are made up of two groups: sugars and phosphates. Use another one of your polymer clay colors to make the phosphate pieces on the double helix.
    • Roll out the color you’ve chosen for the phosphate group until it is flat. Cut strips of the clay ½ inch wide and ½ inch long.
    • Starting at the bottom of one of the long double helix strands, wrap a piece of the flat phosphate clay around the strand.
    • Make sure that it is pressed flat into the helix strand, so that it won’t fall off.
    • Leave half an inch of empty space on the strand, and then add another piece of the flat phosphate clay. The open area of the double helix represents the sugar groups.
    • Continue alternating the clay between the sugar and phosphate ½ an inch apart, until you’ve covered both of the double helix strands.
  4. Create your nitrogenous bases. There are four nitrogenous bases that make up a strand of DNA: cytosine, guanine, adenine, and thymine. They make up the “ladder” steps between the two double helix strands. Choose one color of polymer clay to represent each of these four bases.
    • Roll each color of clay into pieces ½ an inch long, and about ¼ of an inch thick. Use a knife to cut the edges of these, to give them a smooth finish.
    • Count how many sugar groups you have created on your double helix strand. This is the number of pairs of nitrogenous bases you will need to create.
    • Pair off your colors into the correct groups. Cytosine and guanine must always be paired together (in either order), and thymine and adenine must always be paired together (in either order).
    • If you want to give more support to your nitrogenous bases pairs, cut pieces of flexible wire to be just over {{safesubst:#invoke:convert|convert}} long, and use these in the centers of your clay.
    • Combine the pairs of colors by pinching the edges of two strands of your ½ inch pieces of clay together. Once the colors are attached in the center, gently roll the piece to create one smooth, continuous piece of clay.
  5. Attach your nitrogenous bases to the double helix. Once you’ve made all of your {{safesubst:#invoke:convert|convert}} sections of nitrogenous bases, you must stick them to your double helix.
    • Start at the first sugar group on your double helix. Use another small piece of clay the same color as the sugar group, around the size of a pea.
    • Attach one of the nitrogenous bases to the sugar group using the small piece of colored clay. Pinch the pieces together, and smooth the edges by rolling it between your fingers.
    • It may be easiest to attach all the nitrogenous base pieces on one side only to one strand of the double helix. Then, when you have all of the {{safesubst:#invoke:convert|convert}} sections sticking out from one side of the double helix, attach the other strand to the opposite side.
    • Make sure all the pieces are securely attached. If you inserted wire into the centers of your nitrogenous base groups, you can use stick the ends of the wire into the double helix strands to attach it better.
  6. Twist the double helix. To give your DNA model the classic spiral shape, hold your double helix at both ends and then twist them counter-clockwise.
  7. Bake your model. Follow the baking instructions on the polymer clay package, and then bake your model to set its shape.
    • If you have wax paper, set your model on this to make sure it doesn’t stick to your pan.
    • Always allow time for the model to cool after removing it from the oven to avoid burning yourself.
  8. Display your model. Once the model has been baked and cooled, show off your hard work! Hang it with fishing wire from a mobile or your ceiling, or use a wooden base to attach it to.

Making a Model out of Wire and Beads

  1. Gather your supplies. For this project, you will need several feet of a flexible wire, wire cutters and pliers, and beads of your choice.
    • If you wanted to take this project one step further, you could use a soldering iron to attach all the pieces to each other permanently.
    • You can use any beads, although glass beads give the best appearance for this project. Add seed beads (the smallest type of beads) as spacers between larger beads if you prefer.
    • Have at least six colors of beads prepared in a large enough quantity to match the desired size of your project.
    • If you intend on mounting this project for display when you finish, create a base out of wood for your model to be attached to.
  2. Make the double helix. These are the long strands on the sides that hold the ladder-shaped DNA molecule together. Cut two pieces of wire to an equal length; these pieces will make up the body of the DNA model, so make them whatever length you would like depending on how big or small your want your model to be.
    • Choose two colors of beads, and put one on one end of each piece of wire. Wrap the end of the wire through the bead a second time, creating a loop on the outside of the bead. This will prevent the beads from sliding off the end of the wire.
    • Add two colors of beads in an alternating pattern down the wire. The two colors represent the sugar and phosphate groups that make up the length of the double helix.
    • You can choose to use 1 bead of each color or multiple beads of each color, but make sure that you have the same amount of beads for both colors on the wire.
    • Do the same for your other double helix piece of wire, making sure that when the two pieces are set next to each other the colors (sugar and phosphate groups) line up.
    • Leave two inches of empty space at the top of the wire, so that you can attach the “ladder rungs” in the space between beads.
  3. Add the “ladder rungs”. Count the number of sugar groups you created on the double helix, and then cut pieces of wire {{safesubst:#invoke:convert|convert}} long in that number.
    • Wrap the ends of one piece of wire around the double helix wire near to your sugar group beads. Do this for all the pieces, so that you are left with one complete double helix with many pieces of wire sticking out from it.
    • If you want to make a more aesthetically pleasing and sturdier DNA model, use your soldering iron to weld the small pieces of wire to the long double helix strand.
  4. Make your nitrogenous base groups. Choose four other colors of beads, and give them each one of the nitrogenous bases to represent. Guanine and cytosine are always a pair, and thymine and adenine are always a pair.
    • You will probably need multiple beads to fill each little piece of wire, so choose equal numbers of each nitrogenous base beads to attach to the wires.
    • Make sure that you keep your bead pairs in the correct groupings. Always put cytosine and guanine together, and thymine and adenine. You can put them in any order you want though, and have more of some pairs than of others.
  5. Bead your nitrogenous bases. Once you’ve gotten all the beads separated out, place them onto the wire spikes you have sticking out from your one double-helix strand. Be sure to leave a about ½ inch of space at the end of the wire for it to be attached to the other double helix strand.
  6. Attach the other double helix strand. With all the beads added to the nitrogenous base pieces, you can bring your other double helix strand over to attach. Line up the side so that it mirrors the first nitrogenous base, and then attach the small pieces of wire.
    • You can wrap the pieces of wire to the double helix strand using needle-nose pliers. Attach these small bits of wire to the same place you did on the opposing double helix strand.
    • If you are able, you can use your soldering iron to melt the last pieces of wire together, creating a very smooth-looking model.
  7. Cap the ends of your model. To prevent any beads from coming off your model, wrap the wire in a loop around the last bead on each of your double helix strands. You can also choose to solder the wire into a knot-shape to block beads from coming undone.
  8. Twist the double-helix. To create the classic spiral shape of a DNA strand, hold the ends and gently spin them counter-clockwise.
  9. Display your model. once you have added all the finishing touches, your model is complete! Hang it from a mobile or your ceiling using fishing wire, or attach it to a wooden base with a bit more wire or glue. Show off your handiwork![1]

Tips

  • Both these models are a bit too difficult for children, so make sure if you are doing this for a school project that your helping hands are old enough not to hurt themselves on the supplies.
  • Always be careful not to burn yourself if you use an oven or soldering iron to create your DNA model.

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Sources and Citations

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