Chapter 12, Problem 19A

Summary Introduction

To determine:

The type of cell that has many areas of origins of replication

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 identical molecules from one.

Answer to Problem 19A

Eukaryotic cells have many origins of replication. So the cell seen through the microscope must be a eukaryotic cell.

Explanation of Solution

The given diagram shows a cell replicating in several areas. This is a feature of eukaryotes which have many origins of replication. A prokaryotic cell has only one origin of replication.

Eukaryotic DNA unwinds in multiple areas as DNA is replicated. Each individual area of chromosome replicates as a section. The section may vary in length from 10,000 to one million base pairs. This results in multiple areas replicating at one time along the large eukaryote chromosome. Multiple replication origins look like bubbles in the DNA strand.