How to Make DNA Candy Models With a Twist

Designate a type of candy to represent each of the nucleotide bases: adenine (A), cytosine (C), guanine (G) and thymine (T). Gum drops, licorice, marshmallows and gum-based candies work well for this project.

Thread two candies onto a toothpick to represent a pair of bases. A and T always pair together and C and G always pair together. Acceptable combinations are AT, TA, CG and GC. Center the candies on the toothpick. Repeat this step until you have 8 base pairs.

Cut a fruit wrap into strips that are 1/2 inch wide and 1 inch long.

Wrap a fruit wrap strip around a licorice stick every 1/2 inch, so that the color of the licorice stick and the color of the fruit wrap alternate evenly. The fruit wrap stripes represent sugars and the licorice stripes represent phosphates. Secure the ends of the fruit wrap by adding a drop of water to the ends of the strip and pressing them together for several seconds. Repeat this step for the second licorice stick.

Lay the licorice sticks, complete with fruit wrap strips, parallel to each other on a flat surface. Place the toothpicks representing the nucleotide base pairs in between the two licorice sticks. Think of the licorice sticks as the sides of a ladder and the toothpicks as the rungs.

Insert one end of each toothpick into the fruit wrap covered sections of the right-hand licorice strip. Insert the opposite end of each toothpick into the corresponding fruit wrap covered section of the left-hand licorice strip, forming a ladder with eight rungs.

Hold the bottom of the ladder with one hand and the top of the ladder with the opposite hand. Gently twist the DNA ladder; the toothpicks will hold the spiral in place.