Know all the free responses very well. Knowing the free responses will help you on the multiple choice questions.

Warning: Know the details of the experiments (I point out a few particulars below). . .

Experiments that led to the discovery of DNA as the genetic material:
1. Griffith
•Make sure you know the difference between S and R.
2. Avery
•Make sure you know the difference between this experiment and Griffith’s experiment. i.e. how did this experiment “take it to the next level?”
3. Hershey and Chase
•Why did they radioactively label sulfur and phosphorus? You absolutely have to know this!!
4. Chargaff
•This one is a no brainer. . .
5. Meselson and Stahl
•What is density gradient centrifugation and why was it used?
•What is the significance of using different isotopes of nitrogen?
•Know what the results would have looked like for conservative and dispersive replication as well as semi-conservative replication (the true way DNA is replicated).Be able to draw the test tubes for generation 0, 1, 2 for each type of replication. Also be able to draw what the DNA would look like for generation 0, 1, 2 for each type of replication. Look over the animations to get the details right.


Know the basics of DNA as required in the free response question. You do not need to be able to draw the detailed structure but you should know the basic ideas about:
•Naming of the carbons on the deoxyribose sugar
•Sugar-Phosphate backbone and how they are linked
• 5’ to 3’ and what that means
•Nucleotides: Know differences between purines and pyrimidines
•Double stranded nature of DNA and how it is held together
•antiparallel nature of strands

Know DNA Replication very well (hint, hint. . .)
Know all the different enzymes (the main players) in DNA replication and what they do. Know what topoisomerase does and be sure to include it in the answer if this is the free response question.
Be able to illustrate it and describe it in words.
Understand the difference between the leading strand and the lagging strand, the 5’ to 3’ thing, know the importance of Okazaki fragments, realize that DNA replication begins with an RNA primase making a little piece of RNA which has to later be removed (this is strange but true). Know why there are two different types of DNA polymerase and what they do. Be able to relate everything to the replication fork. Remember that the CD ROM does an excellent job: chapter 16 activity. Also, check out the book: page 289, figure 16.16.

Review mismatch repair and excision repair. What is the difference? See pages 289-290, figure 16.17.

Know what a telomere is and what the enzyme telomerase does. See pages 290-291, figure 16.19.