DNA and Protein Synthesis Review



DNA and Protein Synthesis Review

1. What are nucleotides? Describe their structure.

2. Summarize the Hershey and Chase experiment and explain what their results suggested. (radioactive labels; showed that nucleic acid was used to infect)

3. Chargaff made an important contribution to uncovering the structure of DNA. What were his findings and what do they indicate? (complementary base pairing)

4. Who proposed the “double helix” model for the DNA molecule?(Watson and Crick)

5. Describe how DNA and RNA differ in their composition, structure, function, and location.

6. What is meant when we say that DNA replication is complementary? (A-T; C-G)

7. Why is DNA replication important for every cell? (each daughter needs full genome)

8. Compare the amount of DNA in a muscle cell with that in a brain cell. (same)

9. (Meselson and Stahl)What is meant by saying that DNA replication is semi-conservative? (each daughtermolecule has one parent strand and one daughter strand)

10. Briefly describe the steps in DNA replication.

11. Why is replication on one strand of DNA continuous, while on the other strand the replication must be discontinuous? (DNA polymerase works 5'-3' only and strands areantiparallel)

12. What functional group is at the 5' end of a DNA molecule? (phosphate)

13. Proofreading enzymes scan DNA to check for base pairing errors. Explain why these enzymes are important. (to minimize mutations)

14. (same strands - dimer difficult to read; different strands - couldntseparate)Why is the making of exact copies of DNA called replication rather than duplication? (because semi-conservative not original and duplicate)

15. If human DNA contains approximately 3x109 base pairs, and DNA polymerase can work at the rate of about 50 nucleotides per second, how can our DNA be replicated so quickly? (manyorigins and proceeds both strands both directions)

16. If 27 percent of the bases in a certain segment of DNA were adenine, what would be the percentages of thymine(27%), cytosine (23%), and guanine?(23%).

17. A segment of chromosomal DNA which contains instructions for one protein is a _____________.(gene)

18. Describe the technique of DNA fingerprinting.

19. As a research biologist, you know of a bacterium that produces an antibiotic that is quite effective against a certain crop plant fungus. There would be great economic importance in enabling the plant to resist the fungus. How might you use DNA technology to accomplish this?

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