Edible DNA! - Power to Learn

Title: Edible DNA!
Grade Ranges:
___K-4
_X_5-8
___9-12
Subject Tag:
Science: Biology
Science: The Human Body
Synopsis:
Using gum drops and toothpicks, students will build and manipulate a model of DNA in
order to learn its structure and understand how it replicates.
Keywords:
DNA, deoxyribonucleic acid, model, modeling, DNA modeling, genetics, genome, candy
model, heredity, genes, nucleotide, hereditary information
Body: This activity works best as a cooperative group learning activity. Prior to
assigning this activity, have students read about DNA and/or discuss the information in
class. Students should be familiar with nucleotides, the building blocks of DNA. A
nucleotide is made up of three molecules; a sugar, a phosphate group, and a nitrogen
base. A diagram of the DNA model would help students as they work to build the model.
If textbook resources are limited but Internet resources are available, have students visit
http://www.brainpop.com and pick the movie on the genes or DNA for a good (and
funny) overview on the importance of DNA.
Related Links:
Brain Pop
http://www.brainpop.com
great general health, science, and technology resource for middle school kids
DNA From the Beginning
http://www.dnaftb.org/dnaftb/19/concept/index.html
great module that animates the story of how Watson and Crick deduced the structure of
DNA; also has interactive problems and other interesting links
NOVA Online: Hot Science Modules-Journey into DNA
http://www.pbs.org/wgbh/nova/genome/dna.html
Flash plug-in module (and non-flash versions) that allows a student to visualize the
location of DNA in a cell and the structure of the molecule.
Features:
___Contains special education tips
___Quick Activity (less than 30 minutes; story starter)
___Requires Internet access for students to complete
1

Objectives:
1. Students will learn and demonstrate the structure and function of DNA, an essential
component of any cell.
2. Students will learn and demonstrate the replication of DNA.
Standards:
NY: 4.2: Organisms inherit genetic information in a variety of ways that result in
continuity of structure and function between parents and offspring.
NYC: Applied Learning A4 - Learn from models. Life Sciences Concepts S2a - The
student produces evidence that demonstrates understanding of: Structure and function in
living systems, such as the complementary nature of structure and function in cells,
organs, tissues, organ systems, whole organisms, and ecosystems.
CT: 4. Units of Structure And Function: Students will understand that living things share
common materials and structures, which perform basic life functions.
NJ: 5.6: All Students Will Gain An Understanding Of The Structure, Characteristics,
And Basic Needs Of Organisms-10. Identify and describe the structure and function of
cell parts.
Prerequisite Skills:
1. The student must be familiar with the structure of DNA and DNA replication.
Time Required:
45-60 minutes.
Technology and Materials Needed:
1. Spice gum drops (four colors minimum)
2. Orange slices (candy type or some other soft candy larger than gum drops)
3. Plain flat toothpicks
4. Paper towels
Procedures:
*Do all work on paper towels for safety.
Part I: Building a DNA Model
1. Use a diagram of DNA and the key below to build four different nucleotides
(figure 1): See below
Orange slice = deoxyribose sugar Purple gum drop = Thymine nitrogen base
White gum drop = phosphate group Yellow gum drop = Cytosine nitrogen base
Plain toothpicks = chemical bonds Red gum drop = Adenine nitrogen base
Green gum drop = Guanine nitrogen base
Phosphate group
2

Chemical bonds
Deoxyribose sugar
Figure 1: A DNA nucleotide
Nitrogen base (1 of 4)
2. Repeat step 1.
Now, combine the nucleotides to start forming a DNA molecule. DNA has the shape
of a twisted ladder or spiral staircase. The geometric shape is called a double helix.
You will make a "ladder" that has 4 "rungs" or steps. Remember, Adenine combines
with Thymine and Guanine combines with Cytosine. Combine the nucleotides using
the example below (figure 2): See below
Figure 2: Two nucleotides bonded together between the nitrogen bases (a "step")
3. Continue to build the "ladder" combing nucleotides as in step 3.
4. Once you have built the "ladder" that has used all 8 nucleotides made in steps 1
and 2, show the DNA molecule to the teacher.
Part II: DNA Replication (copying)
5. DNA must make a copy of itself before one cell splits into two cells. Special
molecules called enzymes help DNA replicate or copy itself. First, an enzyme
"unzips" DNA as if it were a zipper. Use your hands to pull apart the toothpicks
that hold together your nucleotides (right up the middle like a zipper).
6. Next, an enzyme attaches new nucleotides to the two original strands that were
separated. You will have to make 8 new nucleotides that pair up to the
nucleotides on the original strands. Remember the nitrogen base pairing rules, A
with T and G with C!
7. When you are finished, you should have two DNA molecules that are identical.
Show your results to the teacher and ask him/her if you can eat your results!
8. Clean up your work area.
Assessment Criteria:
1. The student makes DNA nucleotides correctly (Part I).
2. The student builds a simple DNA molecule correctly (Part I).
3. The student successfully replicates the DNA molecule (Part II).
Recommended Lesson Plan Review Date:
6 months
3

Review Comments:
Because web sites are listed as resources, the links should be checked every 6 months.
4

Figure 1: A DNA nucleotide
Phosphate group
Chemical bonds
Nitrogen base (1 of 4)
Deoxyribose sugar

Figure 2: Two nucleotides bonded together
between the nitrogen bases (a “step”)