DNA Replication

DNA Replication

1. Description of DNA Replication

The human body produces billions of new cells every day.  But before undergoing cell division, a cell must first copy the genetic information contained in the cell nucleus – its DNA.  In just 6-8 hours a cell is able to copy its entire genome.  To accomplish this, DNA replication begins at multiple locations along each chromosome.  As the two DNA strands are pulled apart, copying begins at the rate of about 50 nucleotides per second! 

DNA Basics

DNA encodes the information needed to build proteins, to regulate physiological processes and maintain homeostasis in our bodies.  The basic chemical components of DNA are phosphate, deoxyribose (a sugar) and 4 nitrogenous bases: adenine (A), guanine (G), cytosine (C) and thymine (T). 

DNA is a double stranded molecule with the two strands lying antiparallel to each other (they lie parallel to each other but run in opposite directions). The two strands of DNA wind together to form a double helix – a structure that looks similar to a spiral staircase. 

The strands

 of DNA are also complementary to each other due to specific base pairing between the two strands: adenine on one strand will always pair with thymine on the opposite strand and cytosine will always bind with guanine.

During the process of DNA replication, the parental DNA unwinds and since nucleotides have exclusive partners, each DNA can act as its own template for replication.  The two new DNA molecules each consist of one parental strand and one newly made strand.  This is known as semiconservative DNA replication.