DNA Structure Lesson Plan

Instructor: Josh Corbat

Josh has taught Earth Science and Physical Science at the High School level and holds a Master of Education degree from UNC-Chapel Hill.

Just as strands of DNA are the building blocks of life, use this lesson plan to build up your instruction on its basic history and molecular structure. This lesson plan will provide you with a text lesson to jump start your unit as well as a hands-on activity that allows students to build their own blocks of life.

Learning Objectives:

After this lesson, students will be able to:

  • construct a model of the structure of the DNA molecule
  • define key terms associated with the structure of DNA
  • identify the four nitrogen bases that compose DNA
  • summarize the history of human knowledge about DNA


60-90 minutes


  • Toothpicks (enough for approximately 10 per group)
  • Four colors of gumdrops (enough for about 15-25 per group)
  • Licorice (enough for two pieces per group)

Curriculum Standards:


Determine the central ideas or conclusions of a text; trace the text's explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text.


Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 9-10 texts and topics.


Translate quantitative or technical information expressed in words in a text into visual form (e.g., a table or chart) and translate information expressed visually or mathematically (e.g., in an equation) into words.

Key Vocabulary:

  • Adenine
  • Guanine
  • Thymine
  • Cytosine
  • Deoxyribose
  • Phosphate groups


  • Begin this lesson by asking students to name what they already know about DNA (or specifically, the structure of DNA). Write their responses on the board.
  • Provide printed copies of the What is DNA? - Structure, Overview lesson. Have students highlight important information as they read.
  • Next, give student groups (pairs or groups of three or four) the materials listed above.
  • Ask students to use the licorice, toothpicks, and gumdrops to construct a basic model of the DNA molecule. They do not need to pay attention to colors at this point.
    • Walk the room and help groups that may need a bit of prodding. In the end, they should use the two strands of licorice as the 'frames' of the ladder (which will later become the double helix structure), two gumdrops should go onto each toothpick, and each toothpick should be inserted (both ends) into both strands of licorice. This will form what looks like a ladder, which can then be twisted to form a double helix.
  • Now, ask students to build the same model, but to first designate each color of gumdrop as adenine, guanine, thymine, or cytosine. Referring back to the lesson, students will construct a model that pays closer attention to the nitrogen base pairs (adenine with guanine, and cytosine with thymine). Circulate and help groups that are stuck.
  • When groups finish up, have them swap molecules with a nearby group to check that their pairings are all correct.

Discussion Questions

  • Describe the structure of the DNA molecule.
  • What does the licorice in your model represent?
  • What do the toothpicks in your model represent?
  • What do the gumdrops in your model represent?


  • Ask students to refer back to the lesson to pick out all major events in the history of the discovery of the DNA molecule. Have students make a bulleted list of the major events. This can either be turned in for a grade, or you can wrap up the lesson by creating a class list by having students shout out events in order.

Related Lessons:

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