Many students studying DNA structure do not understand or cannot fully visualize the concepts of complementarity, antiparallel, and the organization of the 5’ and 3’ ends of a nucleotide strand. Here, a method that works very well to get students actively involved in the process of describing a DNA molecule is described.   Students themselves are used as the nucleotides in this activity.

Modeling Concepts of 5', 3', Antiparallel, and Complimentarity in DNA Structure (PDF)


Intended Audience








Learning Objectives

After completing this activity, students will be able to:

  1. describe and diagram DNA structure using the following words: complementary and antiparallel.
  2. describe the components of a nucleotide.
  3. label a nucleotide’s 5’ and 3’ end.
  4. label the ends of a string diagram of DNA with 5’ and 3’, knowing one of the ends of one of the strands.
  5. diagram a complementary strand of DNA given the other strand.


Student Background

Students should have prior knowledge about DNA’s role as the genetic material and about the double-helical nature of the DNA molecule. General knowledge about the process of DNA replication, transcription, and translation is also helpful. Additionally, students should:

  • be able to identify the sugar, phosphates, and base of a nucleotide.
  • understand why the carbons of organic molecules are numbered.
  • be familiar with Chargaff’s rules.
  • be able to explain hydrogen bonding and base pairing.



DNA structure, Nucleotide, Purine, Pyrimidine, Antiparallel, Complementarity, 5’ (five prime), 3’ (three prime), Chargaff’s rules


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