FUN CANDY DNA MODEL

Yes, as most of us educators know, most students jump for joy when they hear candy is involved in their lessons. I want to share with you this DNA activity that is always a HIT in my classroom. This is one that, surprisingly, many life science teachers I talked to, said they did not know about. After I tried it with my classes, I made it a must-include-lesson in my DNA unit every year. One, because students enjoyed it, and second, because students learned what I wanted them to about DNA's basic structure.

What I like most about these kinds of lessons, is that they are a hands-on type of activity. Many students learn best by doing and seeing. Reading about DNA's structure won't sink in with all students, they need to see and touch something that represents it. Making their own DNA model will help make the parts of DNA more relatable to those who may be struggling to understand its basic makeup.

 As a teacher, I would recommend walking around the room to ensure all students are on task, and be there to answer any questions. If you want your students to eat their models, have students wash their hands thoroughly before BUILDING and EATING them and sanitize their desks. I usually have students work on a clean paper plate after sanitizing their desks.

If there is not a sink in your classroom for students to wash their hands in, then hand sanitizers are the next best thing. I also like to have plastic storage bags ready for students who want to take their models home to show their parents.

Before students make their candy models, I like for them to create their key on a large index card. On the card, they will choose a color to that will be used for EACH nitrogen base. Depending on what gummy candy they are using, they will choose from the four colors in that type of candy.

I usually recommend gum drops for the bases, but gummy bears can work too. In gum drops, the colors would be usually red, green. yellow, and orange (so each color would represent one of the bases). So, for example, on their index card key if they have Red= Adenine (or A for adenine written in red) and Green= thymine (or T for thymine written in green) then in their DNA model I would want to see that red was always paired with green in their models, since in DNA adenine always pairs with thymine in DNA.

As for the backbone of DNA, the sugar/phosphate "ladder", I like to use Twizzlers for it. And for toothpicks representing the hydrogen bonds, I prefer the toothpicks that have one pointy end and one flat end (less pokes!). They are harder to find in stores, but definitely prefer these over the ones that have two pointy ends.

Materials:

1. Twizzlers

2. Toothpicks (Flat end on one side)

3. Gummy candy (one that a toothpick can easily go through and four different colors)

4. Hand sanitizers

5. Index cards

After students build their DNA models and make their index card key, they then can complete the post lab worksheet. See my example below of the order in which they complete the assignment:

FIRST: MAKE THE KEY

Student Sample

SECOND: BUILD THE DNA MODEL

Once their model is finished, have them gently twist it slightly to create the double helix shape.

Be careful when inserting toothpicks into the licorice. Never hold model in one hand and insert toothpick with other hand, or you make get poked.

THIRD: DNA CANDY MODEL QUESTIONS

*You may download my free DNA CANDY MODEL worksheet to go with this lesson.

Extension

Students can make their model show a mutation (a mismatched base pair). Have them explain where the mutation is to you. They can even use more Twizzlers and gum drops and attach the Twizzlers from one model to two more Twizzlers to make their model even longer! You can tell students to bring extra candy if they want to make a long model. They do look better when students make them 6 or more Twizzlers long. Then gently twist for the double helix shape.