Chapter 12, Problem 4STP

Summary Introduction

Introduction :

DNA replication is one of the most basic process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. DNA is double stranded macromolecule and its strand acts as a template for replication. It is a multistep process. One such step is “unzipping” of DNA replication.

Answer to Problem 4STP

Correct answer :

The correct answer is option (A) DNA helicase.

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) DNA helicase. The enzyme DNA helicasewhich unwinds the double helix by breaking the bonds between two strands and exposes each of the two strands, so that they can be used as a template for replication. Thus, this is the correct answer.

The explanation for the incorrect answer :

Option (B). DNA ligase. DNA ligase is the enzyme that joins DNA fragments together to create one complete DNA strand. Thus, this is an incorrect option.

Option (C).DNA polymerase. It is the enzyme that is ultimately responsible for the creation and expansion of the new strands of DNA. Thus, this is an incorrect answer.

Option (D). DNA primase. DNA primase is the enzyme that attaches to each strand and assembles a DNA primer at which replication can begin. Thus, this is an incorrect answer.