How To Make a DNA Model Using Candy

DNA Model
This model shows the double helix and nucleotide base structure of DNA. The double helix is formed by two spiraling strands of sugar phosphates. Nucleotide bases (red, blue, yellow, green) are arrayed along these strands.

LAWRENCE LAWRY / Getty Images

Making DNA models can be informative, fun, and in this case tasty. Here you will learn how to construct a DNA model using candy. But first, what is DNA? DNA, like RNA, is a type of macromolecule known as a nucleic acid that contains the genetic information for the reproduction of life. DNA is coiled into chromosomes and tightly packed in the nucleus of our cells. Its shape is that of a double helix and its appearance is somewhat of a twisted ladder or spiral staircase. DNA is composed of nitrogenous bases, a five-carbon sugar (deoxyribose), and a phosphate molecule. There are four primary nitrogenous bases: adenine, cytosine, guanine and thymine. Adenine and guanine are called purines while thymine and cytosine are called pyrimidines. Purines and pyrimidines pair together. Adenine pairs with thymine while cytosine pairs with guanine. Overall, the deoxyribose and phosphate molecules form the sides of the ladder, while the nitrogenous bases form the steps.

What You Need:

You can make this candy DNA model with just a few simple ingredients.

  • Red and black licorice sticks
  • Colored marshmallows or gummy bears
  • Toothpicks
  • Needle
  • String
  • Scissors

Here's How:

  1. Gather together red and black licorice sticks, colored marshmallows or gummy bears, toothpicks, needle, string, and scissors.
  2. Assign names to the colored marshmallows or gummie bears to represent nucleotide bases. There should be four different colors each representing either adenine, cytosine, guanine or thymine.
  3. Assign names to the colored licorice pieces with one color representing the pentose sugar molecule and the other representing the phosphate molecule.
  4. Use the scissors to cut the licorice into 1 inch pieces.
  5. Using the needle, string half of the licorice pieces together lengthwise alternating between the black and red pieces.
  6. Repeat the procedure for the remaining licorice pieces to create a total of two strands of equal length.
  7. Connect two different colored marshmallows or gummy bears together using the toothpicks.
  8. Connect the toothpicks with the candy to either the red licorice segments only or the black licorice segments only, so that the candy pieces are between the two strands.
  9. Holding the ends of the licorice sticks, twist the structure slightly.

Tips:

  1. When connecting the base pairs be sure to connect the ones that pair naturally in DNA. For example, adenine pairs with thymine and cytosine pairs with guanine.
  2. When connecting the candy base pairs to the licorice, the base pairs should be connected to the licorice pieces that represent the pentose sugar molecules.

More Fun With DNA

The great thing about making DNA models is that you can use almost any type of material. This includes candy, paper, and even jewelry. You might also be interested in learning how to extract DNA from organic sources. In How to Extract DNA From a Banana, you will discover the four basic steps of DNA extraction.

DNA Processes

  • DNA replication - DNA unwinds in order that copies can be made for mitosis and meiosis. This process helps to ensure that new cells have the correct number of chromosomes.
  • DNA transcription - DNA is transcribed into an RNA message for protein synthesis. The three major steps are initiation, elongation, and finally termination.
  • DNA translation - The transcribed RNA message is translated to produce proteins. In this process, both messenger RNA (mRNA) and transfer RNA (tRNA) work with one another to produce proteins.
  • DNA Mutations - Changes in DNA sequences are known as mutations. Mutations can impact specific genes or entire chromosomes. These changes can be the result of errors that occur during meiosis or by chemicals or radiation known as mutagens.

DNA Basics

DNA Testing

Sources

  • Reece, Jane B., and Neil A. Campbell. Campbell Biology. Benjamin Cummings, 2011.