Date ______
DNA Web Activity
Name ________________
Part 1: The Discovery of DNA
Use the interactive timeline on the website below to answer the following questions.
http://www.learner.org/interactives/dna/history.html
1. What was Griffiths final conclusion in his experiment with the S strain and R strain
_________________________________________
_______________________________________________
______________________________________________
bacteria?
2. How was Avery able to determine that DNA was the transforming factor in Griffith’s
_______________________________________
_______________________________________________
_______________________________________________
experiment?
________________________________
_______________________________________________
3. What is “Chargaff’s Law?”
4. How did Alfred Hershey and Martha Chase determine that DNA is the molecule of
_________________________________________
_______________________________________________
_______________________________________________
heredity?
5. Summarize Rosalind Franklins contribution to the discovery of the structure of DNA.
_______________________________________________
_______________________________________________
_______________________________________________
6. Summarize James Watson and Francis Crick’s contribution to the discovery of the structure of DNA.
___________________________________________________________
___________________________________________________________
Part 2: The Structure of DNA
Use the interactive DNA molecule in the website below to answer the following questions. Use the buttons at the
bottom of the website to manipulate the DNA molecule. Just hit the reset button to go back to the original
molecule.
http://www.umass.edu/molvis/tutorials/dna/dnapairs.htm
1. In your own words described the shape of the DNA molecule shown in the website.
___________________________________________________________
DNA Web Activity
Date ______
Name ________________
2. Using the color code, list the elements that make up a DNA molecule.
3.
4.
5.
___________________________________________________________
What 3 elements make up the nitrogenous bases? ____________________________
What 3 elements make up the DNA backbone? ______________________________
What type of bond holds the two strands of a DNA molecule together? _______________
6. What is the difference in hydrogen bonding between the AT pairs and the GC pairs?
___________________________________________________________
___________________________________________________________
7. What evidence can be seen in the DNA molecule that support that the two strands are
antiparallel? ___________________________________________________
___________________________________________________________
Part 3: DNA Replication
Use the interactive animation below to learn about DNA replication. Begin by clicking on “Basics” at the
menu page.
http://www.learnerstv.com/animation/animation.php?ani=169&cat=biology
______________________________________
___________________________________________________________
1. Explain semi-conservative replication.
2. Using a solid line to represent the parent strand (green in animation) and a dashed line to represent the
new strand (red in animation) draw a diagram the shows the difference in the products of conservative
and semi-conservative replication.
DNA Web Activity
Date ______
Name ________________
Click on DNA polymerase from the menu bar.
_____________________________________
__________________________________________________________
What does DNA polymerase III add to the DNA molecule? ___________________________
3. What is the job of DNA polymerase III?
4.
Click on Okazaki Fragments from the menu bar.
__________________________________________
___________________________________________________________
What is the problem that the replication machinery has to overcome? ____________________
___________________________________________________________
How is this problem overcome? _________________________________________
___________________________________________________________
5. What does antiparallel mean?
6.
7.
8. In the diagram label the following:
leading strand
lagging strand
Okazaki fragment
Also, indicate the 5’ and 3’ end of each strand of DNA.
replication fork