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Importance of dna in biology
The importance of DNA
Importance of dna in biology
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The identification of a substance/phenomenon/condition(s) is the first step toward a new discovery or invention of substantial application (human or otherwise). In the light of this fact, the knowledge of the discovery of DNA is vital to appreciate the beauty of evolution of the events that led to the discovery of DNA. Unlike the common belief that DNA was discovered by the American biologist James Watson and English physicist Francis Crick, the genetic material was first identified by the Swiss physiological chemist Friedrich Miescher in the 1860s. He named them “nuclein”. While having an intention of separating and identifying the proteins present in the white blood cells, he discovered a material inside the white blood cells that were similar to proteins but having high phosphorus content. Sensing the importance of his findings, Miesher wrote “It seems probable to me that a whole family of such slightly varying phosphorous-containing substances will appear, as a group of nucleins, equivalent to proteins”. It was only in 1953, that Watson and Crick put together pieces of experimental information by various investigators to bring forth the three dimensional structure of DNA. Although, various improvisations and extensions have been brought forth to the Watson Crick model, but the four major propositions still remain the same :
• DNA is a double-stranded helix, with the two strands connected by hydrogen bonds. A base are always paired with Ts, and Cs are always paired with Gs, which is consistent with and accounts for ...
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..., with which the redox moiety collides with the electrode and transfers electrons [24]
• The G-rich and C-rich DNAs individually form the parallel G-quadruplex and I-motif, respectively, in the molecular crowding condition, and the 1:1 mixture folds into the parallel G-quadruplex and I-motif but does not form a duplex. The ITC measurements indicated that the thermodynamic stability (ΔG°20) of the duplex formation between the G-rich and C-rich DNAs in the noncrowding condition was −10.2 kcal mol-1, while only a small heat change was observed in the ITC measurements in the molecular crowding condition. These ITC results also demonstrated that the molecular crowding condition prevents any duplex formation between G-rich and C-rich DNAs. These results indicate that a structural polymorphism of the telomere DNAs is induced by molecular crowding in vivo [25]
The molecule consisted of a double helix with phosphates, deoxyribose sugar molecules, and nitrogenous bases. If the spirals were split, the DNA could replicate, which explained why genes were transferred from parents to their children. Additionally, the order of compounds on the DNA indicated that there was a unique ‘code’ on each strand. Watson and Crick believed that this ‘code’ was translated into specific proteins. , ,
The study of nucleic acids has now become a fruitful and dynamic scientific enterprise. Nucleic acids are of unique importance in biological systems. Genes are made up of deoxyribonucleic acid or DNA, and each gene is a linear segment, or polymer, of a long DNA molecule. A DNA polymer, or DNA oligonucleotide, contains a linear arrangement of subunits called nucleotides. There are four types of nucleotides. Each nucleotide has three components; a phosphate group, a sugar and a base that contains nitrogen within its structure. The sugar moiety in DNA oligonucleotides is always dexoyribose, and there are four alternative bases: adenine (A), thymine (T), guanine (G), and cytosine (C). The phosphate groups and the deoxyribose sugars form the backbone of each DNA stand. The bases are joined to the deoxyribose sugar and stick out to the side. Both oligomers, DNA and RNA, consist of 5’->3’ phosphodiester-linked nucleotide units that are composed of a 2’-deoxy-D-ribose (DNA) or D-ribose (RNA) in their furanose forms and a heteroaromatic nucleobase (A, T, G, and C; A, U, G, C), and the resulting oligonucleotide chain is composed of a polar, negatively charged sugar-phosphate backbone and an array of hydrophobic nucleobases. The amphiphilic nature of these polymers dictates the assembly and maintenance of secondary and tertiary structures the oligonucleotides can form. In the DNA duplex structure, genetic information is stored as a linear nucleotide code. This code can be accessed and replicated. RNA, or ribonucleic acid, is another structurally related essential biopolymer. RNA differs from DNA in having the sugar ribose in place of the deoxyribos...
Deoxyribo Nucleic Acid (DNA) is a chromosome found in the nucleus of a cell, which is a double-stranded helix (similar to a twisted ladder). DNA is made up of four bases called adenine (A), thymine (T), guanine (G), and cytosine (C), that is always based in pairs of A with T and G with C. The four bases of A, C, G, and T were discovered by Phoebus Levene in 1929, which linked it to the string of nucleotide units through phosphate-sugar-base (groups). As mention in Ananya Mandal research paper, Levene thought the chain connection with the bases is repeated in a fix order that make up the DNA molecu...
...e molecules, as guanine molecules were similar in number to cytosine molecules (125). Chargaff gathered that DNA of some organisms had excess of A and T, while other forms had excess of G and C (126). With these smaller contributions, Watson and Crick were able to solve the intricate structure of DNA.
o At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water. 3. Explain the basic structure of DNA including base pairing. o 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
By utilizing, and, if possible, modifying this special DNA structure, one may see a reduction of age related illness, diseases, and signs of aging. In this review of human telomeres, we will discuss the roles and functions of the telomere, its structure, and the relation of telomere length to aging and tumorigenesis. Role and Functions of The Telomeres Telomeres are special DNA structures that consist of repetitive nucleotide sequences, which serve as a “cap” to protect the ends of the chromosomes. These repetitive sequences can range from thousands of base pairs in Vertebrates to about a few hundreds of base pairs in yeast cells (Oeseburg, et al. 2009). The 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'Secondary' of the 'S Located at the ends of the chromosomes, the telomeres serve as a biological life line for cells.
Crick discovered the structure of DNA in 1953 and others discovered the genetic code a few years after. The old idea of genes as beads on a string, chromosomes, seemed to gain its vindication from the Watson and Crick model. Each of the three nucleotides in the DNA codes for an amino acid , a string of amino acids makes a protein. Many genes are separated by DNA sequences of nucleotides that are not transcribed into RNA. Proteins are coded by partial sequences on two or more chromosomes. Only a small percentage of DNA codes for proteins are higher than the organisms. In humans DNA codes for proteins are only one percent but not higher than two percent. Many of the rest contain sequences that are repeated over and over again.
With the knowledge of J.M. Gulland and D. O. Jordan’s papers on acid base titrations of DNA, Watson knew that bases form hydrogen bonds to other hydrogens, and that these bonds were present in DNA (183). Watson then thought that DNA had 2 chains with identical base sequences held together with hydrogen bonds, but struggled with figuring out if replication would work perfectly indefinitely, as the wrong bases could bind together (184-188). However, this model was soon found to be incorrect, as thymine and guanine were in enol form in Watson’s model, but should have actually been in keto form (190). Then, with this error found, Watson began rearranging the bases within DNA to see if there were any formations that would not disrupt the structure of the polynucleotide chains as previous models had. After rearranging the bases, Watson discovered that A+T pairs with 2 hydrogen bonds and C+G pairs with at least 2 hydrogen bonds were the same shape, and thus did not bend the chains in a way that was not mathematically possible.
"The discovery of the structure by Crick and Watson, with all its biological implications, has been one of the major scientific events of this century." (Bragg, The Double Helix, p1) In the story of The Double Helix, James Watson tells of the road that led to the discovery of life's basic building block-DNA. This autobiography gives insight into science and the workings within a professional research laboratory that few members of society will ever be able to experience. It also gives the reader an idea of the reality of life for one scientist and how he struggled with the problem of DNA. However, the author's style is marked by his lack of objectivity and inclusion of many biased opinions and personal prejudices.
James Watson, had used most of the information from Franklin presentation and Photo 51 to attempt to build a 3D model of DNA with Francis Crick at Cambridge Cavendish Laboratory. As Petter Portin explains in his article, “The birth and development of the DNA theory of inheritance: Sixty years since the discovery of the structure of DNA,” Watson and Crick used Wilkins, Franklin and Gosling research to create the double helix model that proved accurate in structure to support DNA’s functions, code information on building proteins, auto replicate themselves through complimentary based pairing. The model also later helped to explain how mutation can happen within the nucleotides of DNA. This
Each base are paired up together in order to create DNA. For example, in the article Base pairs it states “Attached to each sugar ring is a nucleotide base, one of the four bases Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). The first two (A, G) are examples of a purine which contains a six atom ring and five atom ring sharing two atoms. The second two (C, T) are examples of a pyrimidine which is composed of a single six atom ring…”
Correspondingly, DNA contains two nucleotides with purine bases and two nucleotides with pyrimidine bases. These nucleotides are labeled adenine (A), guanine (G), thymine (T), and cytosine(C). These parts come in pairs which forms the double helix shape of DNA. Adenine is always paired with guanine and thymine is always paired
The Double Helix tells a tale of fierce competition, perseverance, and scientific innovation as we follow James Watson and his cohort Francis Crick on their quest to discover the secret to life, the structure of deoxyribonucleic acid. Although already fascinated with DNA, Watson struggled with finding chemistry exciting enough to learn it in depth. He had studied birds in college and thereby managed to avoid any formal chemistry or physics courses. As he later pursued a PhD in biochemistry, he realized he could put it off no longer and attempted to learn organic chemistry at Indiana University. However, after a mishap in the lab, he was encouraged instead to study nucleic acid chemistry with Herman Kalckar in Copenhagen. There, his mind strayed from his work and he began doing unauthorized research in the lab of Ole Maaløe, studying phages. Herman stopped teaching Watson after going through a divorce with his wife, and sent Watson off to a scientific conference in Naples. Although he was bored by many of the lectures, Maurice Wilkins’s talk about X-ray diffraction fascinated Watson. He was struck by an X-ray diffraction picture of DNA that Maurice presented and was determined to study the acid. He later got to know more about Maurice’s colleague, Rosalind Franklin, who was proud, stubborn, and very difficult to work with. Watson greatly admired the lecture given by the renowned Linus Pauling, who had discovered the structure of the alpha-helix and was thought of as the leader in DNA research in the scientific world.
The scientific and medical progress of DNA as been emense, from involving the identification of our genes that trigger major diseases or the creation and manufacture of drugs to treat these diseases. DNA has many significant uses to society, health and culture of today. One important area of DNA research is that used for genetic and medical research. Our abi...
How life arose is a question that is fundamental to both philosophy and science. Responses to it enable one, in turn, to answer such questions as, “Who am I?”, “Why am I here?”, and “How do I make sense of this world?” This secondary set of questions can be answered in a myriad of ways for a variety of reasons, but the answer to the first question has only two responses. As Douglas Futuyuma says, “Creation and evolution, between them, exhaust the possible explanations for the origin of living things” (197). Either we are the product of the chemical and physical laws of nature operating over time, or we have been formed, at least in part, by some supernatural Force or Deity. The acceptance of one of these options as a foundation will determine how one will establish a belief system to determine his place in the world. This is a matter of crucial importance, yet in most biology classes offered at U.C. Davis, we learn that life came from nonlife by strictly natural (as opposed to supernatural) processes. The possibility that perhaps the origin of life cannot be explained by a natural mechanism is ignored, and this is disturbing. For if we limit what explanations we are willing to accept for the origin of life, we could be closing our eyes to reality.