Introduction
It is very fascinating to think that nearly all species in life have a stored genetic information that can be passed on from generation to generation, and which controls and accounts for all the biological and phenotypic characteristics in those living organisms. Indeed, deoxyribonucleic acid (DNA) is a macromolecule that has the power of carrying the genetic information for all the proteins that make up an organism and controls their quantity of production. It is known to be located inside the nucleus in all eukaryotic cells, but lies in the cytoplasm in prokaryotic cells (1, 3).
In 1953, Watson and Crick came up with a model to describe the structure of DNA as a double-helix containing two chains that have opposite endings labeled 5’ and 3’, and an anti-parallel orientation, meaning that the 5’ end of one strand is paired up with the 3’ end of the opposite strand. Each chain consists of a number of nucleotides, a structure made of three main components: a phosphate group, a deoxyribose five-carbon sugar and a nitrogen containing base (cytosine, adenine, guanine or thymine).The nucleotides are linked to each other
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The main purpose is to isolate chromatin from both animal and plant tissue. Keeping in mind the structure of DNA described above would help understand how the process of isolation takes place step by step, and the cellular difference between the animal and plant tissue suggest considering different techniques for each type including physical disruption, filtration and centrifugation among others. Relying on these different techniques and methods depending on the cell type, the main goal of this experiment was to isolate the chromatin and extract DNA from strawberries and liver tissue, the extraordinary molecule that carries the entire genetic code for these organisms
Understanding DNA can take a lot of studying and confusion to even get the general idea of the concept. The structure of DNA is very complicated and complex to understand, but researchers James Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin all developed the idea of the DNA structure in 1953. Deoxyribonucleic Acid is found in the nucleus of the cell. It is a double stranded molecule that contains the genetic code and is the main component of chromosomes. DNA is the blueprint of organisms. Nucleotides are the basic unit of DNA and they are made up of sugar, phosphate, and one of the four basis including adenine,
Deoxyribonucleic acid, or DNA as it is most commonly known, is a strand of molecules found within the cell nucleus of all living things. It is called a “genetic fingerprint” because each is different to the other and everyone, apart from identical twins, have
Franklin came very close to realizing this structure. In fact, she had already started to document her work, convinced of the structure; however, there were two key things that she missed. These two things were things she failed to see in her own data, but that Watson and Crick picked up on. The first of the two, which Crick noticed, was the fact that the two strands of DNA run in opposite direction of one another: One goes up and the other goes down. Franklin would have put both strands running in the same direction. Crick picked up on this point from a technical similarity in DNA and the hemoglobin that he was working on [Judson, 1986]. The second point, which Watson discovered, was the unique pairing of the bases in DNA. They are set up such that each strand is complementary to the other and if the two
Structure and function in Biology is a broad concept that can be explored within a diverse range of topics across the subject matter. The following essay will be focussed mainly on the subject of Deoxyribonucleic Acid, or more commonly DNA. DNA is a highly complex, intricate and extraordinary macromolecule found within all living cells. DNA is a "biochemical noun" and can be defined as "...a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information." [Oxford Dictionary, c2016] DNA is found in the nucleus of eukaryotic cells, enclosed within a double membrane. Eukaryotic cells are multifaceted and require a high level of regulation to ensure smooth functioning. The double membrane of the nucleus allows gene expression, a key function of DNA, to be efficiently regulated.
Over the course of the modern age, the human body was still a mystery waiting to be solved. The body contains secrets one can only hope to discover. Over the twentieth century, scientists tried to understand one of the most complex concepts in the biological field. DNA (Deoxyribonucleic acid) was at the forefront of research. Several theories claimed to have solved the structural concept of DNA. However, it was not until Francis Crick and James D. Watson discovered the true structure, the double helix. However, many potential models of DNA had passed through the biology field until eventual lose of credibility. The past models would contain a fixed detail that would make the entire concept invalid. In James D. Watson book, The Double Helix, he illustrates his path amid incorrect theories until he reaches the model that is taught around the world today.
When Pauling and Cory attempted to come up with the structure of DNA, they thought that the DNA helix was a triple helix. This was because they misinterpreted DNA A structure and concluded that the phosphate and sugars were on the inside and the nucleotide bases were on the outside. Watson and Crick said this was not possible because phosphates can’t fit together inside the helix without breaking their molecular bonds. The studies Watson and Crick made were based off of DNA B molecule from the X-ray of DNA B taken by Rosalind Franklin that had low concentration, rather than A DNA which was high in salt concentration that gave Pauling an improper representation of the DNA helix. Pauling and Cory stated that the helix was made of three helices, Watson and Crick disapproved of this concept because phosphate backbones are negatively charged, it was impossible to put three negatively charged strands with each
Deoxyribonucleic acid, or in its’ simple form DNA, contains the code for all characteristics of an organism which is completed by a double helix structure. The structure is made up of a back bone and the four gene groups which include thymine, adenine, cytosine and guanine. The double helix structure contributes to the cell division process
“Eukaryotic cells are complex and include all animal and plant cells. Prokaryotic cells are smaller and simpler, e.g. Bacteria” - (AQA 2008)
The first agarose gel provided insight into whether or not Zassy’s genomic DNA had been cut by the Sal I HF (NEB) restriction enzyme. As seen in Figure 1, Zassy’s cut DNA, in lane 3 left clear fragments between the 3 kb and 0.5 kb areas. Zassy’s uncut DNA, in lane 2, left a clear and bright band above the 10 kb marker. Therefore, the gel confirmed that Zassy’s DNA was successfully cut with Sal I because there was a significant difference the cut and uncut DNA that was run through the gel. There was an additional lane of cut DNA because another student adopted Zassy in the early stages of this experiment. Nevertheless, the clear distinction between lanes 2 and 3 allowed the experiment to continue on to purification of the DNA.
To sum this up DNA is an electronegative molecule with a lacking Oxygen found in the nuclei of Eukaryotes. Now let's go deeper, DNA is not only composed of Sugar, it is also composed of a phosphate backbone, and nitrogenous bases. The phosphate backbone generally expressed as PO4^-3 provides support for the nitrogenous bases [also bonding through ester bonds. The nitrogenous bases in DNA are divided into two Purines [Adenine and Guanine] and Pyrimidines [Thymine, Cytosine, and uracil in RNA] Purines are double ring structures, and Pyrimidines are Single ringed. In other words, they provide the perfect asymmetry of the DNA double helix. When Watson and Crick did their DNA model, they noticed that two Purines bonded together meaning for instance A-G was too wide, and too Pyrimidines bonded together would be too thin. But how did they know which was which? It was found that Adenine always double bonds with hydrogen bonds of course with Thymine, and that Guanine will always triple hydrogen bond with
DNA also known as deoxyribonucleic acid is a complex molecule that carries the genetic information in the cell, essential to build and maintain an organism.
DNA(deoxyribonucleic acid) is a molecule that carries the instructions for reproduction, growth, development, and functioning for all known living organisms.
DNA is a long curved structure, made up of pairs of four specific bases: adenine, guanine, cytosine, and thymine, is the repository of a code from which all of our cells are made. The code is made up of base pairs which look like the rungs of a ladder, and are joined by alternating phosphate and sugar groups, which may be compared to the ladder 's sides or legs. The bases adenine and thymine form what is known as one base pair, and the bases cytosine and guanine form the second base pair.
DNA is a long curved structure, made up of pairs of four specific bases: adenine, guanine, cytosine, and thymine, is the repository of a code from which all of our cells are made. The code is made up of base pairs which look like the
Deoxyribonucleic (DNA) is the molecule that hold the genetic information of living things. In our body every cell contains about 2 meters of DNA. DNA is copied every time a cell divides. Deoxyribonucleic (DNA) is made up of two polynucleotide strands. Polynucleotide strands twist around each other, forming a shape that looks like a ladder called a double helix. The two polynucleotide strands run antiaparallel to each other with nitrogenous bases this means that the stands run in opposite directions, parallel to one another. The DNA molecule consists of two backbones chains of sugars and phosphate groups. The organic bases held together by hydrogen bonds. Although bases bonded together are termed paired