Chapter 15, Problem 8STP

Summary Introduction

Introduction:

The process by which DNA in the chromosome is copied is called DNA replication. Each DNA molecule consists of two strands. Both the strands have complementary base pairs. During replication each strand serves as a template to synthesize new DNA molecule. Replication of DNA produces two molecules from one. Each molecule has one original strand and one new strand.

Answer to Problem 8STP

Correct answer :

The correct answer is option A. addition of binding proteins

Explanation of Solution

Explanation/justification for the correct answer:

Option A. addition of binding proteins- Single stranded DNA- binding proteins called SSB bind to newly separated DNA strands holding them in place and keeping them separated in such a way that the two strands act as template for synthesis of new DNA molecule. The presence of these single strand binding proteins prevents the two DNA strands from reattaching after they have unzipped. Hence this is the correct option.

Explanation for incorrect answer:

Option B. connection of Okazaki fragments- The short, newly formed DNA fragments on the lagging strand are called Okazaki fragments. The connection of these Okazaki fragments to lagging strand does not prevent the two DNA strands from reattaching after they have unzipped. It is the binding proteins that prevent them from coming together. Hence this is not the correct option.

Option C. parting of leading and lagging strands- As the DNA template strands separate, one strand is the leading strand and the other strands is called the lagging strand. The parting of leading and lagging strands does not prevent the two DNA strands from reattaching after they have unzipped. It is the binding proteins that prevent them from coming together. Hence this is not the correct option.

Option D. use of multiple areas of replication- The multiple areas of replication facilitates faster replication of long chromosomes as it occurs at the same time. The presence of single strand binding proteins prevents the two DNA strands from reattaching after they have unzipped. Hence this is not the correct option.