Chapter 5, Problem 2P

Summary Introduction

To examine:  Whether the statement “In E. coli, where the replication fork travels at 500 nucleotide pairs per second, the DNA ahead of the fork-in the absence of topoisomerase-would have to rotate at nearly 3000 revolutions per minute ” is true or false.

Introduction: The replication fork is a Y-shaped structure which moves progressively along the parental DNA double helix. At the replication fork, the DNA polymerase synthesize the DNA of both daughter strands. As the DNA synthesis continues the tension in double strand DNA increases which is relieved by topoisomerase.