DNA Replication Part 3

DNA replication is explained in Detail, Learn it at home and Respond to my questions.
1. What is Function of Topoisomerase?
2. Generation time and DNA replication time in E.coli are 20 minute and 40 minutes respectively, how it is Possible?
3. What is Function of 13mer and 9mer on oriC region?
4. What is Function of CDC6 Protein in Regulation of Polymerisation of DNA?

Link to Video: 
Semester: 
5
Unit: 
2
Subject: 
MICROBIOLOGY
Paper: 
1