Download State what is meant by the topological problem and explain how

BIOLOGY 475: MOLECULAR BIOLOGY
SPRING 2007
1.
State what is meant by the topological problem and explain how DNA topoisomerases solve this problem
2.
Describe the key experiment that proved that DNA replication occurs by the semiconservative process,
3.
Distinguish between the terms 'dispersive', 'semiconservative' and 'conservative', as applied to DNA
replication.
4.
Draw a fully annotated diagram illustrating the Meselson-Stahl experiment. What conclusions can be drawn
from the results of this experiment?
5.
Explain why the discovery of DNA topoisomerases was an important step in the development of knowledge
about DNA replication.
6.
List each component and the function of each component of Escherichia coli the origin in the initiation of
replication
7.
Compare and contrast the Escherichia coli origin of replication with those of yeast and mammals.
8.
What impact does the inability of DNA polymerases to synthesize DNA in the 3
5 direction have on DNA
replication?
9.
State why DNA replication must be primed
10. List the DNA polymerases involved in DNA replication in Escherichia coli and in eukaryotes, and summarize the
function of each enzyme.
11. Explain why the ends of a chromosomal DNA molecule could become shortened after repeated rounds of DNA
replication, and show how telomerase prevents this from occurring.
12. Discuss the links between telomeres, cell senescence and cancer.
13. Draw a diagram of the eukaryotic cell cycle and indicate the periods that act as cell-cycle checkpoints.
14. Outline our current knowledge concerning the composition of pre-replication complexes, the factors that
influence their assembly, and the events that lead to their conversion into post-replication complexes.
15. Describe how genome replication is regulated during S phase.
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