Florida International UniversityPCB 3063

Review Sheet 6

DNA Structure and Function

14.2 DNA Structure and Sequencing

1)What are the building blocks of DNA?

2. What are the components of a nucleotide?
3. What are the nitrogenous bases?
4. What sugar is in DNA and what sugar is in RNA?
5. What is the name of the bond that links one nucleotide to another in the formation of nucleic acids?
6. Describe the structure of a purine and a pyrimidine.
7. How are the carbon atoms of the five-carbon sugar numbered?
8. Describe the 5’-3’ phosphodiester bond.
9. What was Pauling’s contribution to the determination of the structure of DNA?
10. What tool was Rosalind Franklin using to understand the structure of DNA?
11. Who were awarded the Nobel Prize for determining the structure of DNA?
12. Why wasn’t Franklin included in this group?
13. Describe DNA’s structure.
14. What are the complementary base pairs? How are they stabilized?
15. What does it mean when it’s said that the two strands are antiparallel in nature?
16. What makes up the backbone of the structure and what is stacked inside?
17. How many base pairs are there per turn of the helix?
18. What pairings explain the uniform diameter of the molecule?
19. What role does the major and minor grooves serve?
20. Who developed the sequencing method used for the human genome sequencing project?
21. What is gel electrophoresis?
22. What hominid was the closest ancestor of present-day humans?
23. When did they disappear from the fossil records?
24. What did their genome show that seems to contradict the view that all present-day humans can be traced to a small ancestral population in Africa?

25. What genes (governing what traits) seem to have undergone changes from those ancestors during the evolution of present-day humans?

DNA Packaging in Cells

26. Describe the typical prokaryotic chromosome and where it is located.
27. How does DNA fit inside a small bacterial cell?
28. Name a protein/enzyme that helps maintain the supercoiled structure?
29. How do Eukaryotes fit their DNA inside the nucleus?
30. Describe a nucleosome.
31. What are the heterochromatin and euchromatin?
    2. – Basics of DNA Replication

1. What were the 3 models for DNA replication?
2. Which model is correct?
3. Describe how this model works?
   3. – DNA replication in Prokaryotes

1. Give a brief description of the DNA replication in E. coli.
2. What is the role of DNA polymerase?

3. Where is the energy that is used in the addition of nucleotides?
4. What are the roles of DNA pol I, DNA pol II, and DNA pol III?
5. Describe the origin of replication in E. coli.
6. What enzyme unwinds the DNA and how does it do it?
7. Describe the replications forks.
8. What is the role of the binding proteins?
9. What is the direction in which a new DNA strand can be extended>
10. If a free 3’-OH group is needed to add a nucleotide, then how does it add the first nucleotide?
11. Describe the primer and what enzyme makes it.

12. What is the role of topoisomerase?
13. What are Okazaki fragments?
14. What is the role of ligase?
15. How quickly does the replication fork move?
16. What does it mean when we say the DNA double helix is anti-parallel?
17. What does that mean for the new daughter strands? [remember, semi-conservative replication means the double stranded DNA separates and each of the old strands (parental) acts as a template for the new strands (daughter)]
18. How many primers are needed for the leading strand and how many are needed for the lagging strand?
19. What is the role of the sliding clamp?

1. 4. – DNA Replication in Eukaryotes
1. The human genome has how many base pairs per haploid set of chromosomes?
2. What is the rate of replication in eukaryotes and humans can have up to how many origins of replication?
3. How many DNA polymerases are there in eukaryotes?
4. What is the role of helicase?
5. The leading strand is synthesized by what enzyme and the lagging strand by what enzyme?
6. Describe what happens at the end of a linear chromosome due to there being no place for a primer to be made for the DNA fragment of be copied of the end of the chromosome.
7. What are telomeres and what is there role during division?
8. What is the 6 base pair sequence in human telomeres?
9. Describe the telomerase enzyme and its role in the replication process.
10. In which cells are telomerase active and not active?
11. How is telomere shortening associated with aging?
12. What is the role of telomerase in cancer cells?

1. 5. – DNA Repair
1. How are most mistakes during DNA replication corrected?
2. If a mistake is found, what happens?