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CareerStart lessons: Grade seven

LEARN NC was a program of the University of North Carolina at Chapel Hill School of Education from 1997 – 2013. It provided lesson plans, professional development, and innovative web resources to support teachers, build community, and improve K-12 education in North Carolina. Learn NC is no longer supported by the School of Education – this is a historical archive of their website.

Learning outcomes

Students will learn about the process of DNA extraction and will gain an understanding of how scientists use DNA.

Teacher preparation

Time required for lesson

One to two class periods (45-55 minutes)

Materials needed

  • Computer with internet access
  • Student handouts:
    • Strawberry DNA extraction directions — one copy for each student
    • “Search for Answers” worksheet — one copy for each student
  • One heavy-duty zip-lock baggie
  • One strawberry (fresh or frozen and thawed)
  • Cheesecloth or coffee filter
  • Funnel
  • Test tube
  • Glass rod or pipette
  • One dram container (optional)
  • Reagents:
    • DNA extraction buffer: 50 ml liquid dishwashing detergent (Ivory), 15 g NaCl, and 950 ml water
    • Ice-cold 95% ethanol or 95% isopropyl alcohol


  1. Ask the students to explain DNA. What role does it play in our bodies, in plants, and in animals? (DNA is the genetic code that makes up everything that we are.)
  2. Ask students to brainstorm what careers would use DNA in their profession. (genetic counselors, OBGYN, forensic scientists, etc.)
  3. Hand out the strawberry DNA extraction directions and walk students through the process of extracting DNA from a strawberry. The following directions are on the student handout:
    1. Place one strawberry in a zip-lock baggie.
    2. Smash strawberry with fist for 2 minutes.
    3. Add 10 ml extraction buffer to the bag.
    4. Smash again for one minute.
    5. Filter through cheesecloth or coffee filter in a funnel into test tube.
    6. Holding test tube at an angle, slowly pour the ice-cold alcohol into the tube until the test tube is half full.
    7. At the interface, you will see the DNA precipitate out of solution and float to the top.
    8. You may spool the DNA on your glass rod or pipette tip.
    9. Fill 1 dram container ½ full with ethanol or isopropyl alcohol.
    10. Dip glass rod or pipette tip containing DNA into the 1 dram container and cap.
  4. Put students into pairs. Hand out the “Search for Answers” worksheet and have students reseach forensic scientists in their pairs.


Optional resources for more information on the topics covered in this lesson

Understanding Genetics: Human Health and the Genome
Students can click on the Tech Museum of Innovation’s online exhibit “Zooming into DNA” to understand and visualize where DNA in your body is.
DNA Extraction Virtual Lab
The University of Utah’s virtual lab gives students the opportunity to perform a cheek swab and extract DNA from human cells online.
neoK12: Genetics
neoK12 provides educational videos, lessons, and games for students about genetics that have been reviewed by K-12 teachers.
Explain that Stuff!: Forensic Science
This website provides detailed information about how forensic scientists use science to solve crimes, from the crime scene to the lab.
FBI Kids Page
The FBI Kids Page is designed for students to learn more about the FBI through developmentally appropriate and interactive games, tips, and stories. They also introduce viewers to their working dogs and explain how FBI agents and analysts investigate cases.
CSI: The Experience - Web Adventures
On this interactive website, students can solve crimes with CSI agents and learn about forensic science.

North Carolina curriculum alignment

Science (2005)

Grade 7

  • Goal 1: The learner will design and conduct investigations to demonstrate an understanding of scientific inquiry.
    • Objective 1.09: Use technologies and information systems to:
      • Research.
      • Gather and analyze data.
      • Visualize data.
      • Disseminate findings to others.
  • Goal 5: The learner will conduct investigations and utilize appropriate technologies and information systems to build an understanding of heredity and genetics.
    • Objective 5.01: Explain the significance of genes to inherited characteristics:
      • Genes are the units of information.
      • Parents transmit genes to their offspring.
      • Some medical conditions and diseases are genetic.

  • Common Core State Standards
    • English Language Arts (2010)
      • Science & Technical Subjects

        • Grades 6-8
          • 6-8.LS.3 Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.
        • Grades 9-10
          • 9-10.LS.3 Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.

  • North Carolina Essential Standards
    • Science (2010)
      • Biology

        • Bio.3.3 Understand the application of DNA technology. Bio.3.3.1 Interpret how DNA is used for comparison and identification of organisms. Bio.3.3.2 Summarize how transgenic organisms are engineered to benefit society. Bio.3.3.3 Evaluate some of the ethical...
      • Grade 8

        • 8.L.2 Understand how biotechnology is used to affect living organisms. 8.L.2.1 Summarize aspects of biotechnology including: Specific genetic information available Careers Economic benefits to North Carolina Ethical issues Implications for agriculture