Adapted from NOVA Activity: Cracking the Code of Life
Biotechnology Workshop A: Cheek Cell Extraction
LEARNING GOALS: After the completion of this workshop, students will understand:
1.
2.
3.
Students will learn a simple DNA extraction procedure
Students will learn the function of DNA and how DNA is contained within cells
Students will learn how DNA can be isolated from cells by performing a DNA extraction from
the own cheek cells
CONCEIVE – What do I wish to accomplish through this project?
This stage involves guiding students in defining the goals of the project, then helping them
develop conceptual, technical and action plans to meet those goals while considering the
technology, knowledge, and skills that apply. This guidance is provided in the form of Essential
Questions that use student’s preconceptions, and misperceptions then move them toward a
deeper and more realistic understanding of the process and skills needed to complete the
project.
ESSENTIAL QUESTIONS:
1. What is DNA? Where is it housed within a cell?
2. What does DNA do? What can DNA tell us?
3. How can we isolate DNA?
NOTES: Each step in the process of DNA extraction should be explained for additional
concept clarity.
DESIGN - How will I accomplish the project?
1. An introductory lecture will provide students with the basic knowledge needed to
complete this workshop. This lecture should cover some cell biology terms, such as
DNA, chromosome, cell lysis, isolation, and extraction.
2. Additionally, further concept clarification will be provided throughout the students’
working time.
3. Explain how each reagent and how each step contributes to the eventual DNA isolation.
Copyright University of Colorado Colorado Springs, 2011. For permission to use these materials, contact the Director at the
Center for STEM Education, (719) 255-3595. Curriculum format design adapted from CDIO developed by MIT.
NOTES: In the P Drive, “DNA Necklace kit instructions.docx” provides sufficient
background information for this project.
IMPLEMENT - From an idea to a product!
Procedure: This procedure will collect some of the buccal cells that line the inside of your
mouth. These cells are continuously being sloughed off by your cheeks.
1. Swill 2 teaspoons (10ml) 0.9 percent salt water in your mouth for 30 seconds.
2. Spit the water into your cup. Pour this into a large test tube containing 1 teaspoon (5
ml) 25 percent liquid detergent.
3. Cap tube and gently rock it on its side for 2–3 minutes. The detergent will break open
the cell membrane to release the DNA into the soap solution.
4. Open and slightly tilt the tube and pour 1 teaspoon (5 ml) fluid ounces of the chilled 95
percent ethanol down the side of the tube so that it forms a layer on the top of your
soapy solution.
5. Allow tube to stand for 1 minute.
6. Place a thin acrylic or glass rod into the tube.
7. Stir or twirl the rod in one direction to wind the DNA strands onto the rod. Be careful to
minimize mixing of the ethanol and soapy layers.
8. After you have wrapped as much DNA onto the rod as you can, remove the rod and
scrape/shake the DNA into a small tube containing the rest of the 95 percent ethanol.
Your DNA should stay solid in this solution.
NOTES: In this activity, you’ll break away the membrane around the cell and its nucleus so
that you can see your very own DNA.
OPERATE – Does it work the way I planned?
Do not be too vigorous while mixing in step three. DNA is a very long molecule. Physical abuse
can break it into smaller fragments, a process known as shearing. If too much shearing has
occurred, the DNA fragments may be too short to wind up, and they may form clumps instead.
You can try to scrape these out with the rod.
Students may take home their DNA within a small centrifuge tube.
RESOURCES NEEDED – What equipment and supplies do I need?
Copyright University of Colorado Colorado Springs, 2011. For permission to use these materials, contact the Director at the
Center for STEM Education, (719) 255-3595. Curriculum format design adapted from CDIO developed by MIT.
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Microcentrifuge pendant tubes
15 mL tubes
1-oz plastic cups
Plastic pipets (3-mL, graduated)
Colored string to make necklace with pendant tube
25-mL bottles of cell lysis solution (liquid detergent)
100-mL bottles of chilled 95% ethanol
.9 percent salt water
Glass rods
SET-UP
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Chill the ethanol by storing it in the freezer or a bucket of ice until ready to be used.
Pour salt water solution into plastic cups for each student.
Cut the string such that there is enough for each student to have one.
Set up a solution station for dispensing the cell lysis solution or have bottles of
detergent available for students.
 Each student also gets a 15-mL tube, a plastic pipet, and a pendant tube.
Copyright University of Colorado Colorado Springs, 2011. For permission to use these materials, contact the Director at the
Center for STEM Education, (719) 255-3595. Curriculum format design adapted from CDIO developed by MIT.
Colorado State Standards - High School
21st Century Skills
2. Life Science
Students can:
a. Develop, communicate, and justify
an evidence-based scientific
explanation of how cells form
specialized tissues due to the
expression of some genes and not
others
b. Analyze and interpret data that
show most eukaryotic
deoxyribonucleic acid (DNA) does
not actively code for proteins within
cell
Concepts and skills students master:
6. Cells, tissues, organs, and organ
systems maintain relatively stable
internal environments, even in the face
of changing external
environment
8. Multicellularity makes possible a
division of labor at the cellular level
through the expression of select genes,
but not the entire genome
Colorado State Standards – Eighth Grade
21st Century Skills
2. Life Science
Students can:
a. Develop, communicate, and
justify an evidence-based
scientific explanation for how
genetic information is passed
to the next generation
b. Use direct and indirect
observations, evidence, and
data to support claims
about genetic reproduction and
traits of individuals
Concepts and skills students master:
2. Organisms reproduce and transmit
genetic information (genes) to offspring,
which influences individuals’ traits in the
next generation
Inquiry Questions:
1. How are traits passed from
one generation to the next?
Colorado State Standards – Seventh Grade
21st Century Skills
2. Life Science
Inquiry Questions:
1. How does each body system
contribute to supporting the life of
the organism?
2. How do organs and organ systems
in the human body interact to
perform specific functions?
Concepts and skills students master:
2. The human body is composed of atoms,
molecules, cells, tissues, organs, and
organ systems that have specific functions
and interaction
Copyright University of Colorado Colorado Springs, 2011. For permission to use these materials, contact the Director at the
Center for STEM Education, (719) 255-3595. Curriculum format design adapted from CDIO developed by MIT.