Question

SELLUN 9. Contrast the functions of DNA polymerase III and DNA polymerase I. 10. Why do are the start points of DNA replication in eukaryotic and prokaryotic organisms AT rich? 11. What is the start point of DNA replication called in E. coli? What is it called in humans? 12. In DNA replication in E. coli which enters the replication fork first, DnaA protein, or Helicase? 13. In eukaryotes, two proteins are involved in linking DNA replication to S phase of the cell cycle. a. What are these proteins called? b. how is it that they are linked to the cell cycle?

Answer 1

DNA Replication is the process in which DNA makes its own copy by a special process called DNA Replication. For this process, there is a need for a bunch of enzymes and out of them, DNA polymerase is one of the essential enzymes for DNA replication.
Answer 1
There are 3 important DNA polymerase enzyme namely DNA polymerase I, DNA polymerase II, and DNA polymerase III.
Key differences between DNA polymerase I and II is
DNA polymerase I work on lagging strand or discontinuous strand to remove RNA primer and replace it with DNA. It shows proofreading activity from 5'-3' direction it is in contrast with DNA polymerase III which is 3'-5' direction.
DNA polymerase III is important for the synthesis of DNA strand from 5'-3' direction on both leading and lagging strand during DNA replication.

Answer 2
The A-T region is thermodynamically less stable than G-C region where A-T having 2 hydrogen bonds and G-C have 3 so likely A-T can break easily and double DNA strand separate into single strand so all replication machinery attached this site and replication will continue.

Answer 3

The origin of replication in prokaryotes or in E Coli is OriC. Single-origin and circular DNA. While in human or eukaryote multiple origins of replication and linear DNA.

Answer 4
Helicase is the enzyme which first attached to DNA for unwinding DNA molecule and then other protein and enzyme involved in the process of DNA replication.
DnaA protein is important in recognition of the origin of a replication site.

I'm supposed to answer the only first 4 questions, please separately the last one

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