1. A nucleotide is made of three parts: a ___________________ group, a five carbon __________________, and a nitrogen containing _____________________

2. In a single strand of DNA, the phosphate group binds to the __________________ of the next group.

3. The 5' end of a single DNA strand contains a free __________________, while the 3' end contains a free __________________________.

4. Chromosomes consist of what two substances: ____________________ & ______________________

5. DNA was not thought to be the genetic blueprint originally; instead many scientists hypothesized that _______________________ contained the genetic code and blueprint of life. (They were later proven wrong.)

6. Purines have _________ rings, and pyrimidines have ____________ ring.

7. Check each of the following statements that are true with regard to Griffith's experiments.

______ Griffith discovered transformation in bacteria.
______ Mice injected with non-encapsulated bacteria quickly became sick and died.
______ Encapsulated bacteria can become "naked" bacteria.
______ Bacteria that are naked tend to be harmless.
______ Naked bacteria can develop a capsule only after exposure to the DNA of encapsulated bacteria.
______ Griffith's transforming factor was the protein in the capsule.
______ Heating the encapsulated bacteria preventing transformation of the naked variety.
______ Transformation allows bacteria to acquire new genes.
______ Enzymes that destroyed DNA would prevent transformation.

8. Check each of the following statements that are true with regard to the Hershey-Chase experiment.

_______ DNA was labeled with radioactive phosphorous.
_______ Protein was not labeled.
_______ Radioactive sulfur was found in the offspring phages after they emerged from the cell.
_______ Phage proteins were not transmitted to host cell or to offspring.

9. Chargaff's rule states that the DNA of any species contains equal amounts of __________________ & ____________ and also equal amounts of __________________ & ____________________

10. Wilson and Franklin studied the structure of DNA using _________________________ and determined that the shape of the molecule was a __________________

11. James Watson and Francis Crick amended Franklin and Wilson's conclusions and determined that the shape of the molecule was instead a _________________ __________________

12. In DNA, thymine is complementary to ________________ ; cytosine is complementary to _____________

13. In a strand of DNA, the percentage of thymine is 30 %. What is the percentage of cytosine in the same DNA strand? _________________

14. Number the steps of DNA replication in the correct order (1, 2, 3)

_______Daughter strands are formed using complementary base pairing.
______ DNA unwinds
______ The DNA of the daughter strands winds with together with its parent strand.

15. Why is DNA replication called "semi-conservative"? __________________________________________

16. What enzyme unwinds are unzips the parent strand? ________________

17. The junction between separated strands is called the ________________________________

18. What enzyme synthesizes the new DNA strand? _______________________

19. What enzyme binds fragments of DNA on the lagging strand? ______________________

20. DNA polymerase only travels in the ________ to _________ direction.

21. On the diagram:

Label the 3' and 5' ends.

Circle a nucleotide.

Label the sugar and phosphate.

Label the bases that are not already labeled

22. The two sides of the DNA helix are held together by ________________________

23. Write out the complete name for DNA: __________________________________________

24. Name the scientist(s) responsible for each of the following discoveries.

_____________________________________ Bacterial transformation
_____________________________________ The base-pair rule
_____________________________________ DNA was the hereditary material of viruses
_____________________________________ The shape of DNA was a helix
_____________________________________ The shape of DNA was a double helix

25. In your own words, explain why the discovery that DNA was the molecule of heredity was an important discovery.