It's easy to make a DNA model out of candy. You'll learn how the DNA molecule is constructed, plus you can eat your science project as a snack.
The Structure of DNA
In order to construct a model of DNA, you need to know what it looks like. DNA or deoxyribonucleic acid is a molecule shaped like a twisted ladder or double helix. The sides of the ladder are the DNA backbone, made up of repeating units of a pentose sugar (deoxyribose) bonded to a phosphate group.
The rungs of the ladder are the bases or nucleotides adenine, thymine, cytosine, and guanine. The ladder is twisted slightly to make a helix shape.
Candy DNA Model Materials
You have several options here. Basically, you need 1-2 colors of rope-like candy for the backbone. Licorice is good, but you can find gum or fruit sold in strips, too. Use 3 different colors of soft candy for the bases. Good choices include colored marshmallows and gumdrops. Just be sure to choose a candy you can puncture using a toothpick.
- licorice
- small colored marshmallows or gummy candy (4 different colors)
- toothpicks
Construct the DNA Molecule Model
- Assign a base to a candy color. You need exactly four colors of candies, which will correspond to adenine, thymine, guanine, and cytosine. If you have extra colors, you can eat them.
- Pair up the candies. Adenine binds to thymine. Guanine binds to cytosine. The bases to not bond to any others! For example, adenine never bonds to itself or to guanine or cytosine. Connect the candies by pushing a matched pair of them next to each other in the middle of a toothpick.
- Attach the pointy ends of the toothpicks to licorice strands, to form a ladder shape.
- If you like, you can twist the licorice to show how the ladder forms a double helix. Twist the ladder counterclockwise to make a helix like the one that occurs in living organisms. The candy helix will unravel unless you use toothpicks to hold the top and bottom of the ladder to cardboard or styrofoam.
DNA Model Options
If you like, you can cut pieces of red and black licorice to make a more detailed backbone. One color is the phosphate group, while the other is the pentose sugar. If you choose to use this method, cut the licorice into 3" pieces and alternate colors on a string or pipecleaner. The candy needs to be hollow, so licorice is the best choice for this variation of the model. Attach bases to the pentose sugar parts of the backbone.
It's helpful to make a key to explain the parts of the model. Either draw and label the model on paper or attach candies to cardboard and label them.
Quick DNA Facts
- DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are nucleic acids, an important class of biological molecules.
- DNA is the blueprint or code for all of the proteins formed in an organism.
- New DNA molecules are made by breaking the ladder shape of DNA down the middle and filling in the missing pieces to make 2 molecules. This process is called transcription.
- DNA makes proteins through a process called translation. In translation, the information from DNA is used to make RNA, which goes to the ribosomes of a cell to make amino acids, which are joined to make polypeptides and proteins.
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