Chapter 24, Problem 5P

5.

Summary Introduction

To determine: The amount of base pairs present in a closed-circular DNA molecule in its relaxed form that has an Lk of 500.

Introduction:

Linking number for a circular DNA molecule should be intact, without a cut to possess topological characteristics. During the relaxed form, the linkage number (Lk) is equal to the number of turns found in the DNA double helix. A closed-circular DNA molecule contains an Lk of 500 in its relaxed form.

(a)

Summary Introduction

To determine: The way through which Lk altered, when a protein complex binds to form a nucleosome.

Introduction:

In a double stranded DNA, linking number is a topological characteristics, it does not vary whether the DNA is deformed or bent. It causes both DNA strands to remain intact. Linking number can be written as Lk.

(b)

Summary Introduction

To determine: The way through which Lk altered, when one strand is broken.

Introduction:

In a double stranded DNA, linking number is a topological characteristics, it does not vary whether the DNA is deformed or bent. It causes both DNA strands to remain intact. Linking number can be written as Lk.

(c)

Summary Introduction

To determine: The way through which Lk altered, when DNA gyrase and ATP are added to the DNA solution.

Introduction:

In a double stranded DNA, linking number is a topological characteristics, it does not vary whether the DNA is deformed or bent. It causes both DNA strands to remain intact. Linking number can be written as Lk.

(d).

Summary Introduction

To determine: The way through which Lk altered, when the double helix is determined by heat.

Introduction:

In a double stranded DNA, linking number is a topological characteristics, it does not vary whether the DNA is deformed or bent. It causes both DNA strands to remain intact. Linking number can be written as Lk.