How topoisomerases unknot knots that are formed in DNA
Introduction:
The study of properties of geometric objects under deformations is called topology; the subfield of topology that I will be discussing in this essay is called knot theory (Adams 6). Mathematical knots have two primary differences: one, they are infinitely thin, and two, they are always closed. Something very similar to the size and shape of mathematical knots is DNA. Not surprisingly, knots occur in DNA frequently on a normal basis.
DNA, short for Deoxyribonucleic Acid, is a molecule found in pairs in the shape of the double helix strands. The strands are composed of “sugars and phosphates,” and the pairs of bases are Adenine, Thyamine, Cytosine, and Guanine, or A, T, C, and G, respectively. Also, A is always paired with T while C is always paired with G. Knots in DNA make “biological functions” like replication, transcription, and recombination difficult to achieve (Adams 182). Fortunately there are enzymes called topoisomerases that find these knots and remove them from the DNA strand so that it is able to function easily (Adams 182). This is important because knots reduce the stability of DNA (Adams 182).
Mathematical Context:
The mathematical origins of knot theory traces back to the early nineteenth century works of Gauss, Listing, Helmholtz, Kelvin, Maxwell, and Talt (Sumners 39). In the beginning, Johann Frederich Carl Gauss, a German mathematician, who was interested in the idea of knots, contributed “analysis situs,” which describes the
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mathematical differences between simple and complex knots, to knot theory (Davis). Later on, more scientists became interested in knots. They believed that the universe was made up of an invisible and frictio...
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...lary that is easy to comprehend. Biochemists are experimenting and working hard to answer these difficult questions about how the different topoisomerases enzymes work to unknot knots in DNA.
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Resources
1. Adams, Colin. The Knot Book: An Elementary Introduction to the Mathematical Theory of Knots. Providence, Rhode Island: American Mathematical Society, 2004.
2. Sumners, De Witt. “Knot Theory and DNA.” Proceedings of Symposia in Applied Mathematics Volume 45 (1992): 39.
3. Knot Theory Online: The Web Site for Learning More about Mathematical Knot Theory. Payne, Bryson and Nardo. North Georgia College and State University. August 3, 2005.
4. Knot Theory History. Davis, Jim. August 3, 2005.
5. “Tangles in Biology.” pages 25-31.
Encyclopedia Britannica Online. Encyclopedia Britannica, n.d., pp. 113-117. Web. The Web.
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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. , ,
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In April of 1953, James Watson and Francis Crick published a game changing paper. It would blow the mind of the scientific community and reshape the entire landscape of science. DNA, fully knows as Deoxyribonucleic Acid is the molecule that all genes are made of. Though it is a relatively new term with regard to the age of science, the story of DNA and the path to its discovery covers a much broader timeframe and had many more contributors than James Watson and Francis Crick. After reading the paper the audience should have a better understanding of what DNA is, the most important experiments that contributed to its ultimate discovery and the names and contributions of the lesser-known scientists that helped Watson and Crick turn their idea
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...
The first and primary contribution to solving the DNA structure was the relationship of Crick and Watson. Without their teamwork and determination, another scientist would have discovered the structure before them. One of Crick’s bigger contributions was discovering the gene is self-replicating. After talking with John Griffith, Crick came up with the idea that the gene is self-replicating, meaning the gene has the ability “to be exactly copied when the chromosome number doubles during cell division”(126). With further discussion with Griffith, Francis believed that DNA replication involved specific attractive forces between the flat surfaces of the bases (128). One of Watson’s major contributions was after seeing the B form of DNA by Franklin, Watson knew that the structure of DNA was two-chained and that led to the building of the model of DNA (171). Also through research, Watson became aware that adenine and thymine pair together and are held by two hydrogen bonds that were identical in shape to the guanine and cytosine pair held together by at least two hydrogen bonds (194). This discovery showed that the two chains of DNA are complementary to each other. With these individual contributions coming together, Watson and Crick successfully were able to piece together the structure of DNA.
strands which make up the letters of a genetic code. In certain regions of a DNA strand
The 'lock and key' hypothesis explains how enzymes only work with a specific substrate. The hypothesis presents the enzyme as the 'lock, and the specific substrate as 'key'. The active site binds the substrate, forms a product, which is then released. Diagram 1- a diagram showing the 'lock and key' mechanism works
A predicament has occurred, in which you speak in the defense of a young female, considered to be guilty on the basis of hair color. Knowledge of the structure of DNA and its role in heredity, how DNA and RNA work together to produce proteins, and how brown hair can result from various gene combinations , will all be an important asset in determining if the young lady is guilty or not.
Michael Guillen, the author of Five Equations that Changed the World, choose five famous mathematician to describe. Each of these mathematicians came up with a significant formula that deals with Physics. One could argue that others could be added to the list but there is no question that these are certainly all contenders for the top five. The book is divided into five sections, one for each of the mathematicians. Each section then has five parts, the prologue, the Veni, the Vidi, the Vici, and the epilogue. The Veni talks about the scientists as a person and their personal life. The Vidi talks about the history of the subject that the scientist talks about. The Vici talks about how the mathematician came up with their most famous formula.
"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.
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DNA (deoxyribonucleic acid) is a self-replicating molecule or material present in nearly all living organisms as the main constituent in chromosomes. It encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Simply put, DNA contains the instructions needed for an organism to develop, survive and reproduce. The discovery and use of DNA has seen many changes and made great progress over many years. James Watson was a pioneer molecular biologist who is credited, along with Francis Crick and Maurice Wilkins, with discovering the double helix structure of the DNA molecule. The three won the Nobel Prize in Medicine in 1962 for their work (Bagley, 2013). Scientist use the term “double helix” to describe DNA’s winding, two-stranded chemical structure. This shape looks much like a twisted ladder and gives the DNA the power to pass along biological instructions with great precision.
Abstractions from nature are one the important element in mathematics. Mathematics is a universal subject that has connections to many different areas including nature. [IMAGE] [IMAGE] Bibliography: 1. http://users.powernet.co.uk/bearsoft/Maths.html 2. http://weblife.bangor.ac.uk/cyfrif/eng/resources/spirals.htm 3.