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Lesson Plans
The Ladder of Life

Cindy Jackson
OverviewProcedure for teachersStudent Resources and Materials
Grade Level
Time Alloment
 Three 50-minute periods


In this lesson and its extensions, students will learn practical applications of DNA profiling and the role it plays in today's forensic science. DNA extraction is a fundamental concept in the field of forensics and biotechnology. Students should have previous knowledge of the contents in DNA and RNA. Through video and Web-based activities, the students will develop a greater understanding of what DNA does in a cell. Students will be able to assemble DNA parts in order to simulate DNA strands. They will also have the opportunity to experimentally view DNA through an extraction technique included in the lesson.

Learning Activities

Students will be able to:

  • Understand the concepts of what DNA is and where it is located in a cell
  • Identify the two types of molecules that make up the rungs of a DNA molecule
  • Identify the two types of Purine and Pyrimidine molecules
  • Explain how the molecules Adenine, Thymine, Guanine, and Cytosine can only be combined in four ways
  • Explain, define, and apply DNA extraction techniques
  • Examine and describe the physical structure of DNA


National Science Education Standards

As a result of activities in grades 9-12, all students should develop the abilities necessary to do scientific inquiry and understandings about scientific inquiry.

As a result of their activities in grades 9-12, all students should develop understanding of the molecular basis of heredity and the cell.

Media Components


Cell Biology Resource, Episode #5: "DNA – Replication and Mitosis"

Web Sites:

DNA assembly

This Web site allows students to become familiar with the basic components of DNA. The interactive component of the site allows students to reconstruct DNA using guanosine, adenine, thymine, and cytosine.

Virtual Berkley Laboratories

In the reality-based tour of Berkley Laboratories, students can view the various equipment used in DNA extraction. To ensure you can adequately see the lab, download Apple QuickTime Virtual Reality software before viewing the site. The above address has a link to allow for the download.

Microscopes, Cells, DNA and You

This is a Web site where teachers can find various types of lesson plans and teaching materials that will further their understanding of DNA.


Per Group of Two:

  • Tongue depressors
  • Glue gun
  • Two-foot long strips of 1/4" wide elastic (one strip randomly marked in 1 inch color segments using blue, red, green, and purple)
  • Set of 4 markers (one of each color - blue, red, green, and purple)
Per Group of Four:
  • Raw, untreated wheat germ (1.5 g)
  • 2 small beakers
  • 1 N sodium bicarbonate (10 ml)
  • 2 small test tubes
  • Palmolive liquid dish detergent (5ml)
  • 1 glass rod (Pasteur pipette)
  • Meat tenderizer (3g)
  • 2 graduated cylinders
  • 95% ethyl alcohol (ice cold)
  • 1 plastic spoon
  • Hot water bath at 55 degrees Celsius
  • 1 balance (triple beam or digital)
  • Small bowl of ice
  • Hot plate
Per student:
  • Lab instruction sheet