History of DNA WebQuest


1.     Friedrich (Fritz) Miescher


Find Miescher on the timeline and click on the bucket with the Red Cross to watch the animation.  In 1869, he extracted a substance from white blood cells that he called nuclein.  What do you think he was actually extracting? 



2.     Frederick Griffith



Frederick Griffith’s famous experiment was conducted in 1928.  In his experiment, ______________ smooth virulent bacteria plus live rough ______________ bacteria killed mice.  His experiment demonstrated that DNA was the _______________ material.   


Griffith’s Famous Experiment: Transformation




3.     Oswald Avery


In 1944, what did he discover that DNA is responsible for? 






4.     Alfred Hershey and Martha Chase



a.      In 1952, their experiments showed that ______ is the genetic material instead of ____________. 



5.     Erwin Chargaff


Watch “Chargaff’s Ratios.”  Chargaff used relative proportions of bases in DNA to come up with his rules for base pairing.  What are four sources of DNA that he used?



Adenine (A) pairs with _____________

Guanine (G) pairs with _____________

The bases that are purines include ___________ & ____________.

The bases that are pyrimidines include ___________ & ______________.



6.     Rosalind Franklin



http://www.dnai.org/timeline/index.html - Watch Franklin’s X-ray diffraction pattern


What is X-ray crystallography (a.k.a. X-ray diffraction)?



What did she discover about the shape of DNA?


7.     Linus Pauling

http://www.dnai.org/timeline/index.html - Watch the animation.

Linus Pauling proposed a structure for DNA that was incorrect.  Describe or draw it below:





8.     Maurice Wilkins


His research, with the help from ________________, led to the discovery of the DNA molecule structure.  This discovery was made by American biologist, ________________, and British physicist, ________________.


9.     James Watson and Francis Crick



a.      What did they receive the Nobel Prize for in 1962? 


b.     What is the difference between Pauling’s structure and the actual structure of DNA?



10. DNA Game


    Play the game and record what three organisms you had: