DNA Structure Questions for Students

DNA Structure: http://molvis.sdsc.edu/dna
Teachers: see the Lesson Plan.

You are not expected to know all the answers. Use the buttons in the DNA tutorial to investigate. Play around with the DNA molecule to try to figure out the answer to a question! If you find the questions too hard, you may find it useful to visit Andrew Carter's introductory story about DNA Structure.

    Question Set A (for ages 14 and older)

  1. What is a "strand" of DNA?
  2. How many strands make up a DNA double helix?
  3. Each strand is made up of two zones or regions. One zone of each strand is made up of identical repeating units, while another zone is made up of differing units. What are these zones of each strand called?
  4. What holds one strand against the other in the double helix?
  5. How do cells make accurate copies of DNA?
  6. When do cells duplicate their DNA?
  7. What information is coded into DNA?
  8. What is a "codon"?
  9. What is "transcription" of DNA?
  10. What is "translation" of DNA?

  11. Question Set B (for ages 18 and older)
  12. What are the four pairs of DNA bases that form in the double helix?
  13. How can A distinguish T from C?
  14. Which DNA double helix do you think would be harder to separate into two strands: DNA composed predominantly of AT base pairs, or of GC base pairs? Why?
  15. What is a mutation?
  16. The DNA double helix looks like a twisted ladder. What makes up each rung of the ladder? What holds the rungs together at the sides?
  17. Is there mostly empty space between the atoms in a DNA double helix?
  18. One base pair is not in position to form normal Watson-Crick hydrogen bonds. Can you find it? (Note: Clicking on any base in D. Ends, Antiparallelism reports its letter and sequence number at the bottom of the browser window in the status line, following the word "Group". Use this feature to obtain the letters and sequence numbers of the abnormal base pair, once you find it.)
  19. How do proteins recognize specific sequences of DNA? (More about this.)

  20. Question Set C (for ages 20 and older)
  21. Which bases are purines? Pyrimidines?
  22. If a purine were substituted for a pyrimidine at a single position in one strand of a DNA double helix, what would happen?
  23. In a DNA double helix, why doesn't an A or T form two hydrogen bonds (out of the three possible) with G or C?
  24. How many kinds of 5-membered rings are in DNA?
  25. How many kinds of 6-membered rings are in DNA?
  26. Does the "free arm" of deoxyribose (the carbon that is not a member of the pentose ring) point in the direction in which the coding strand is read, or against it?
  27. Based on the codons shown (in the Codons movie in section B. The Code), is the DNA strand shown the template strand or the coding strand?

Answers are available to teaching faculty who inquire with an email to Eric Martz providing evidence of their faculty positions, such as by reference to a school or college website listing faculty.

Questions by Frieda Reichsman (MoleculesInMotion.Com) and Eric Martz.
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