Dna Replication Essay examples

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DNA REPLICATION

WHAT IS DNA?

DNA is a molecule that has a repeating chain of identical five-carbon sugars (polymers) linked together from head to tail. It is composed of four ring shaped organic bases (nucleotides) which are Adenine (A), Guanine (G), Cytosine (C) and Thymine (T). It has a double helix shape and contains the sugar component deoxyribose.

THE PROCESS OF DNA REPLICATION

How DNA replicates is quite a simple process. First, a DNA molecule is “unzipped”. In other words, it splits into two strands of DNA at one end of the DNA molecule. This separation will cause a formation of a replication fork.
After the replication fork has been established the strands of DNA are ready for the next stage. On each strand is a sequence
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 The first discovery Chagraff made was that the amount of adenine present in all DNA molecules is equal to the amount of thymine.
 The second discovery Chagraff made was that the amount of guanine was equal to the amount of cytosine.
 The third discovery Chagraff made was that the amount of adenine plus thymine often differs greatly from the amount of guanine plus cytosine.

HOW THE IMAGE OF DNA WAS FIRST DISCOVERED

After Chagraff’s discoveries, two British scientists by the name Rosalind Franklin and Maurice Wilkens were able to apply his observations. Thus, these two scientists were the first ones to discover the image of what a DNA molecule actually looked like in three-dimension.
     How these scientists manage to obtain the image of a DNA molecule was by the use of “x-ray crystallographic analysis”. In this process, DNA molecules are bombarded with a x-ray beam. These x-rays encounter atoms, which in turn causes their paths to bent or diffract. The pattern created by the sum of total of these diffractions are then captured on a photographic film. The pattern is then interpreted into the image of the molecule through careful analysis. Thus, because of this research it led to the first theory and model structure of DNA.

MAURICE WILKENS
     
Maurice Wilkens was born in the year 1916 and is a British
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