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
The four names of the nitrogenous bases of the DNA are adenine, thymine, guanine, and cytosine. The word "adenine" was created in the 19th century in German from the Greek words “adēn” "gland" and "in". The word "cytosine" was coined in the 19th century from the German word "cytosin" from cyto- "cell", -ose and the chemical suffix -ine. The word "guanine" comes from the English words "guano" and "ine" and was also created in the 19th century. The word “thymine” comes from words “thymus” and the suffix -ine.
In the early 1950s, the race to find the structure of DNA was in full swing. The search was being conducted at three different colleges. At the California Institute of Technology, Linus Pauling,
1. What role did Rosalyn Franklin play in our understanding of DNA’s structure? She discovered the double-helix position of the DNA.
Chapter 1: Genes can be demonstrated as “instruction books for making functional markers such as ribonucleic acid(RNA) and proteins”(Chapter 1, page 4). Distinctively, the four nitrogenous bases to code the gene of DNA is adenine, thymine, guanine, and cytosine. In addition, Rosalind Franklin was among the primitive people to experiment with X rays as a form of molecular photography in order to learn more about DNA and its structure. The structure of DNA taught a constitutional fact about genetics; it stated that the two strands of DNA were complementary to each other. Moreover, DNA replicates in order to make new sets of
In Time Magazine an article states On February 28 1953, James Watson and Francis Crick broke the DNA code and discovered that the DNA strand is double helix and forms like a ladder. They found that cytosine and guanine were paired together and that adenine and thymine were paired. They discovered the building block of life (Wright, 1999). DNA is found in all living organisms.
Two people not in the Cavendish lab, but equally as involved in the discovery of the structure of DNA were Maurice Wilkins and Rosalind Franklin, from King's College in London. While writing about many of the afore-mentioned individuals Watson emitted a constant attitude of indifference and his actions toward Rosalind Franklin equally reflected that indifference.
Ok let's break DNA down first. DNA stands for Deoxyribonucleic acid. Deoxyribose is referred to the absence of an O in the Carbon 2 of the ribose pentose. DNA is made up of six smaller molecules a five-carbon sugar called deoxyribose, a phosphate molecule and four different nitrogenous bases adenine, thymine, cytosine and guanine. The basic building block of DNA is called a NUCLEOTIDE. A nucleotide is made up of one sugar molecule, one phosphate molecule and one of the four bases. In other words, the sugar that makes DNA is ribose a pentose sugar in the case of this molecule DNA its lacking an Oxygen in its carbon 2. Nucleic is referred to its position, our DNA most anyways is located on the nucleus of our cells, the presence of this nucleus is what differs us from Prokaryotes us being Eukaryotes.
Rosalind Franklin was able to take an x-ray image of the DNA strand and see how it was shaped. After seeing her work James Watson and Francis Crick took her image and began researching into it. This led them to discover the double helix.
# Explain the process by which DNA is able to make copies of itself also including an explanation of why it is considered semiconservative replication - There are four steps to replication
Watson and Crick discovered that cell’s nucleuses contained a molecule that was called deoxyribonucleic acid, or DNA. The clues from the diary are: “Even us lab boys knew that there had been gossip going around the labs that Crick and Watson had been trying to solve the structure of this new-fangled molecule called DNA – deoxyribonucleic acid – but discovering the secret of life itself?”
The origins of DNA were first discovered during 1857 by Gregor Mendel the "Father of Genetics”, whom was performing an experiment of genetics with pea plants, and would provide a basic foundation towards DNA and Genetics. Friedrich Miescher and Richard Altmann in 1869 were also part of the first people to discover DNA. While testing some sperm of a salmon, they discover a strange substance that they would name as "nuclein", which is known as DNA. This new form of "nuclein" (DNA) would be found to only exist in chromosomes. Frederick Griffith, a researcher, found the basis on DNA, from a molecule inheritance experiment involving mice and two types of pneumonia. His findings were that, when virulent disease is heated up (to kill) and is
The work of these four people led to a complete restructuring of the beliefs of the scientific community regarding genetic information. Their initial word led to further work which encompassed their hypothesis of how DNA replicates itself. From this work came the modern technologies of DNA fingerprinting and sequencing.
Transcription is where DNA is transcribed into RNA which then can be pass to the ribosome’s to act as a template for protein synthesis. Before transcription can begin DNA must unwind and the two halves of the molecule much come apart so exposing the base sequence. This process begins when a region of a two DNA strands is unzipped by enzyme called RNA polymerase attaches to the DNA molecule at the imitation site.
Hershey and Chase Radioactively tagged and then tracked infected bacteria in order to prove that DNA was in fact the molecule of heredity and transferring of genetic material
The process of DNA replication plays a crucial role in providing genetic continuity from one generation to the next. Knowledge of the structure of DNA began with the discovery of nucleic acids in 1869. In 1952, an accurate model of the DNA molecule was presented, thanks to the work of Rosalind Franklin, James Watson, and Francis Crick. To reproduce, a cell must copy and transmit its genetic information (DNA) to all of its progeny. To do so, DNA replicates following the process of semi-conservative replication. Two strands of DNA are obtained from one, having produced two daughter molecules that are identical to one another and to the parent molecule. This essay reviews the three stages