Download DNA From the Beginning WEBQUEST

Name:
Date:
Structure of DNA and DNA Replication Web Quest
Go to www.dnaftb.org and then complete the following web quest: Answer your questions on that
document. Print when finished or email to Mrs. Berthelot: [email protected]
Click on the link “Molecules of Genetics”, then click on Lesson 15 (DNA and proteins are key molecules of the
cell nucleus) and then the link “Animation”.
1. Read through the animations and then answer the following questions:
a. What contribution did Miescher make to the study of DNA?
b. What contribution did Levene make?
c. What were the two possible candidates for the genetic material? Why?
2. Answer the “problem” on this page.
a. Why was Levene wrong?
3. Click on #17 on the side menu, “A gene is made of DNA” Click on animation.
a. Describe Frederick Griffith’s experiment.
b. What was the difference between the R strain and the S strain?
c. What did Griffith discover?
d. How did Avery and his colleagues improve on Griffith’s experiment?
e. What was Avery able to show about DNA?
4. Click on # 18 “Viruses and bacteria have DNA too”. Click on animation.
a. How were Hershey & Chase able to prove that it was definitely DNA (not protein) that was
the genetic structure?
5. Click on # 19 “The DNA molecule is shaped like a twisted ladder”. Click on animation.
a. What did Chargaff discover about DNA?
b. What did Linus Pauling discover that helped Watson and Crick?
c. What is X-Ray crystallography?
d. Draw the two pictures of DNA from X-ray crystallography.
e. Why was Linus Pauling’s model of DNA wrong?
f. Describe the structure of DNA based upon Watson and Crick’s observations. Include:
i. Hydrogen bonds
ii. Double helix
iii. Antiparallel
iv. The four bases: cytosine, adenine, thymine and guanine
g. Complete the Problem on this section:
i. Draw the correct DNA model
ii. Write the correct sequence
iii. How is DNA antiparallel?
DNA REPLICATION – visit the following website
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http://nobelprize.org/medicine/educational/dna_double_helix/index.html
Click on “Play the DNA – The Double Helix Game”
Play the game, placing the correct bases with the complement. Make sure you move
quickly!
Answer the questions:
a. Identify organisms and number of chromosomes:
1.
2.
3.
b. How many mutations are ‘allowed’ in the human genome? Why do you think this is?
c. What was your score? How many mutations did you have for each organism?