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
Andrew Carter's introductory story about DNA Structure.
Question Set A (for ages 14 and older)
- What is a "strand" of DNA?
- How many strands make up a DNA double helix?
- 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?
- What holds one strand against the other in the double helix?
- How do cells make accurate copies of DNA?
- When do cells duplicate their DNA?
- What information is coded into DNA?
- What is a "codon"?
- What is "transcription" of DNA?
- What is "translation" of DNA?
Question Set B (for ages 18 and older)
- What are the four pairs of DNA bases that form in the double helix?
- How can A distinguish T from C?
- 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?
- What is a mutation?
- 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?
- Is there mostly empty space between the atoms in a DNA double helix?
- 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.)
- How do proteins recognize specific sequences of DNA?
(More about this.)
Question Set C (for ages 20 and older)
- Which bases are purines? Pyrimidines?
- If a purine were substituted for a pyrimidine at a single
position in one strand of a DNA double helix, what would happen?
- 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?
- How many kinds of 5-membered rings are in DNA?
- How many kinds of 6-membered rings are in DNA?
- 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?
- 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 firstname.lastname@example.org providing evidence of
their faculty positions, such as by reference to a school or
college website listing faculty. I will not send answers unless you
tell me your full name, position (student, teacher, etc.), institution,
city/state, country. If you are not a teacher, please tell me the
name and email of your teacher, and your teachers website if there is one.
Questions by Frieda Reichsman
Feedback to Eric Martz.