Making a DNA model is a great way to learn how this fantastic structure forms our genes. With materials that you can easily find at home, you can build your own model and combine science with the arts to make a beautiful project.
Steps
Method 1 of 3: Building a Model with Pipe Cleaners and Beads
Step 1. Get the supplies
You will need at least 4 pipe cleaners 12 inches (30 cm) long and assorted beads in six different colors.
- Plastic beads work best for this project, but you can use any type of bead, as long as they have a hole large enough to thread through the pipe cleaners.
- The pairs of pipe cleaners must be of different colors. They can be orange and black, as you'll eventually use one of these pairs to represent phosphates and deoxyribose.
Step 2. Cut the pipe cleaners
Take 2 pipe cleaners of the same color and cut them into strips that are 2 inches (5.1 cm) wide. You will use them to string the beads, making pairs, C with G and T with A. You must leave the other pair of pipe cleaners as is, without cutting it.
Step 3. Thread the beads into the pipe cleaners that form the double helix
Use beads of two different colors to represent sugars and phosphates, then string them onto each pipe cleaner, alternating colors.
- Make sure that both chains that make up the double helix are the same, so that the beads are in the same order.
- Leave a ½ inch (1 cm) space between each bead to place the pipe cleaner strips that make up the nitrogenous bases.
Step 4. Thread the beads into the pipe cleaners for the nitrogenous bases
Take the other beads of four different colors and make pairs with them. The pairs have to be made of the same colors to represent guanine that goes with cytosine and thymine that goes with adenine.
- Attach a bead to each end of the 2-inch (5.1 cm) strips. Always leave a little space at each end to bend the pipe cleaner and put it on the double helix.
- It doesn't matter what order you put the pairs in, as long as you've put the right colors in each pair.
Step 5. Attach the pipe cleaners
Attach the 2-inch (5.1 cm) strips of pipe cleaners to the longer ones, folding their ends to do so.
- Place the small pipe cleaners on a bead of the same color on each side. Skip the bead that is not that color before placing the next pipe cleaner.
- The order in which you put the small pipe cleaners does not matter; it is up to you how you are going to organize them.
Step 6. Bend the propeller
When you've attached all the pipe cleaners, bend the ends of the double helix counterclockwise to make it look like a real DNA chain. Now you can enjoy your finished model!
Method 2 of 3: Build a Model with Styrofoam Pellets
Step 1. Get the supplies
For this version of the project, you will need small Styrofoam balls, a needle and thread, paints, and toothpicks.
Step 2. Paint the Styrofoam balls
Choose paints in six different colors to represent the sugars and phosphates, in addition to the four nitrogenous bases. Choose the colors of your preference.
- You need to paint 16 sugar balls, 14 phosphate balls and four different colored balls for the nitrogenous bases (cytosine, guanine, thymine and adenine).
- One of the colors you can choose is white, so you don't have to paint all the balls. The easiest thing will be that the sugar balls are the white ones so as not to have so much work.
Step 3. Form the nitrogenous base pairs
When the paint dries, choose a color for each of the nitrogenous bases and make the appropriate pairs. Cytosine always goes with guanine and thymine always goes with adenine.
- The order of the colors does not matter, as long as the pairs are correct.
- Prick the balls that make up each pair with a toothpick, pushing them inwards so that there is a space at each end of it.
Step 4. Form the double helix
With the needle and thread, cut a piece of thread long enough to thread 15 Styrofoam balls. Tie a knot at one end of the string and thread the other end of the thread onto the needle
- Line up the sugar and phosphate balls well, alternating colors until you have 15 balls on each side. There will be more sugar balls than phosphate.
- Make sure the sugar and phosphate chains are the same so you can line them up when you put them next to each other.
- Thread the sugar and phosphate balls onto the string through the center of each one. Tie a knot at the other end of the thread so that the balls do not come out.
Step 5. Place the nitrogenous bases on the double helix
Take each toothpick with the nitrogenous bases and place them on the sugar balls, pinching them.
- You should place the pairs on the polystyrene balls that represent the sugar, since this is how the real DNA is formed.
- Make sure each toothpick is held securely against the double helix so that the nitrogenous bases don't fall off easily.
Step 6. Bend the propeller
When you have added all the nitrogenous bases to the sugar, fold the strand of the double helix counterclockwise to make it look like a real DNA strand. You just finished your model!
Method 3 of 3: Build a Candy Model
Step 1. Choose the sweets
To make the sides of the phosphate and sugars, use black and red licorice candies that have a hollow center. To form the nitrogenous bases, use four different colors of gummy bears.
- Whatever type of candy you use, make sure it is soft enough that you can poke it with a toothpick.
- If you have colored marshmallows on hand, you can use them in place of the gummy bears.
Step 2. Prepare the other materials
Find a string and several toothpicks to build your model. The string should be cut into several strips of 1 foot (30 cm) each, although they can be longer or shorter depending on the size of the model.
- Use two strips of string that are the same length to form the double helix.
- Make sure you have at least a dozen toothpicks, although you may need more or less depending on how big you want your model to be.
Step 3. Cut the licorice candies
You will thread them onto the string, alternating colors, so you should cut them into 1 inch (2.5 cm) long strips.
Step 4. Arrange the gummy bears in pairs
In a DNA strand, cytosine and guanine (C and G) go together, just like thymine and adenine (T and A). Pick four different colors of gummy bears to represent these nitrogenous bases.
- It does not matter if the pair is C with G or G with C, as long as they are the ones that make up the pair.
- You cannot mix colors between the pairs, for example, you cannot place T with G or A with C.
- The colors you choose do not matter, you can choose the ones you want.
Step 5. Thread the licorice candies on the string
Take the 2 strips of string and tie a knot at the end of each one so that the candy does not come out. Then thread each candy on the string through the hole in the center, alternating colors.
- The colors of the licorice candy symbolize the sugars and phosphates that are part of the double helix chain.
- Pick a color to be the sugar; This is where you will place the nitrogenous bases of bears.
- Make sure both strings of candy are the same so you can line them up well when you place them next to each other.
- Tie a knot at the other end of the string, once you have finished adding all the pieces of the licorice candy.
Step 6. Prick the gummy bears with the toothpicks
When you have made the pairs of gummy bears, C with G and T with A, place one of the gummy bears at one end of the toothpick and the other bear at the other end.
- Push the gummy bears inward until a 1/4 inch (0.6 cm) tip pops out of each end of the toothpick.
- You can have more of one type of pair than the other. The number of pairs in the actual DNA determines the differences between each gene.
Step 7. Place the pairs of bears in the licorice candy
Put both candy chains on a flat surface and then poke them with the bear toothpicks and thus add the nitrogenous bases.
- Remember to place the pairs on the "sugar" molecules of the color you decided on. They all have to be the same color (for example, all red pieces).
- Use all the toothpicks, so don't save any.
Step 8. Bend the propeller
When you've attached all of the bear toothpicks, fold the DNA strands counterclockwise to give the molecule the spiral appearance of a real double helix. Now you can enjoy your finished model!