Chapter 25, Problem 35CQ

Summary Introduction

To explain: The reason why a DNA polymerase that could synthesize DNA in the 3′→5′ direction would have a selective advantage even if it has 5′→3′ proofing activity.

Introduction: DNA polymerases function as synthesizing DNA strand by the polymerization of the nucleotides in the growing chain. The DNA template is read in 3′→5′ direction of the strand to synthesize a DNA in 5′→3′ direction. It has also 3′→5′ DNA synthesis activity for lagging strand synthesis. In addition, it has 5′→3′ proofing activity. However, the DNA synthesis in 3′→5′ direction is more advantageous to the host.