Name (Last, First): Discussion Unique No.:
Discussion Questions Set #7 October 18 2005
Please turn in a printed/written copy of the questions with the answers to two
questions for the next discussion session.
DNA Replication
1. Briefly describe semi-conservative DNA replication and
bidirectional DNA replication.
2. Define origin of replication and mention characteristic DNA
elements in it. Do not include actual DNA sequence in your
answer.
3. a. Compare E.coli DNA polymerases I and III in terms of their
enzymatic activities with specified directionality such as
polymerization and exonuclease avtivities.
b. Why does E.coli use DNA polymerase III? Why can it not use DNA
polymerase I?
4. What are the role(s) of the following proteins in DNA replication
in E.coli.
a. DnaA
b. DnaB
c. DnaC
d. SSB
e. DNA polymerase I
f. DNA gyrase
g. DNA primase: Compare it with RNA polymerase
h. DNA ligase
i. DNA polymerase III (holoenzyme): include the function of its
-subunit and -clamp in your answer
j. DNA topoisomerase I
5. a. List and compare the precursors and enzymes needed to
synthesize the leading and lagging strands during DNA
replication in E.coli.
b. Does leading strand require DNA primase?
