Chapter 13, Problem 3Q

Summary Introduction

To review:

Whether deoxyribonucleic acid (DNA) replication form its starting point is bidirectional or unidirectional.

Given:

In an experiment, a pulse and chase method were applied to the cells and the DNA extracted from them was subjected to the gel electrophoresis.

Figure 1: DNA bands representing a pulse and chase method.

Introduction:

The duplication of DNA takes place during the S phase of the cell cycle. If the cells are subjected to the medium containing radioactive thymidine during this phase, then the DNA extracted from them can be observed in the gel electrophoresis.