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Because then the DNA can hold more info
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∙ 12y ago
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What are the applications of DNA topology?
DNA topology is the focus of an interdiscipline between molecular biology and mathematics and as a term refers to DNA supercoiling, knotting and catenation. More simply put, DNA topology studies the shape and path of the DNA helix in three dimensional space. The topology of DNA topoisomers is important to replication, transcription and recombination, including the recombination events important to the life cycles of many viruses. Topoisomerases are enzymes that change the topology of DNA. DNA Topology starts with a basic account of DNA structure before going on to cover DNA supercoiling, the definitions and physical meanings of linking number, twist, and writhe, and the free energy associated with supercoiling. It then considers the rather more complex description of DNA lying on a curved surface and its application to the nucleosome, followed by the phenomena of DNA knotting and catenation
How DNA recoiling into helix?
DNA has the property of two types of coiling:- neative supercoiling and positive supercoiling. It means that it uncoil from one side and at the same time recoil from the next side. the uncoiling is subjected by helicases enzyme and topoisomerases and the ssbp's (single stranded binding proteins let the DNA to stabilize and lets replication to start. while at the same time the DNA recoils from another side, it does so bcoz there is no ssbp's to stabilize DNA so that it doesnt recoil, therefore it recoils.
How do DNA gyrases and helicases differ in their respective functions and modes of action?
Helicases are involved in the unwinding of DNA double helix at the replication fork. When one part of the DNA is unwound the other part is overwound which exerts strain. DNA gyrases introduces negative supercoiling to reduce the strain.
How does DNA make itself more compact?
wrapping tightly around associated proteins
How does ethidium bromide interact with double stranded DNA Does it increase or remove supercoiling?
when ethidium ion intercalates between two dna base pairs in a circular dna it causes the dna to unwind by 26 degrees, thereby decreasing twist and increasing writhe. in a circular dna which is negatively supercoiled, if ethidium is added it will become relaxed and if more ethidium is added dna becomes positively supercoiled
How is DNA supercoiling regulated?
Plick, plack, plock.Pintyremalengaaratongcerapack.Preperry.
What protein assists DNA in supercoiling?
Histon Protein
What must be done in order for DNA to fit into a cell?
Coiling , recoiling ,supercoiling .
What are the applications of DNA topology?
DNA topology is the focus of an interdiscipline between molecular biology and mathematics and as a term refers to DNA supercoiling, knotting and catenation. More simply put, DNA topology studies the shape and path of the DNA helix in three dimensional space. The topology of DNA topoisomers is important to replication, transcription and recombination, including the recombination events important to the life cycles of many viruses. Topoisomerases are enzymes that change the topology of DNA. DNA Topology starts with a basic account of DNA structure before going on to cover DNA supercoiling, the definitions and physical meanings of linking number, twist, and writhe, and the free energy associated with supercoiling. It then considers the rather more complex description of DNA lying on a curved surface and its application to the nucleosome, followed by the phenomena of DNA knotting and catenation
How DNA recoiling into helix?
DNA has the property of two types of coiling:- neative supercoiling and positive supercoiling. It means that it uncoil from one side and at the same time recoil from the next side. the uncoiling is subjected by helicases enzyme and topoisomerases and the ssbp's (single stranded binding proteins let the DNA to stabilize and lets replication to start. while at the same time the DNA recoils from another side, it does so bcoz there is no ssbp's to stabilize DNA so that it doesnt recoil, therefore it recoils.
How do DNA gyrases and helicases differ in their respective functions and modes of action?
Helicases are involved in the unwinding of DNA double helix at the replication fork. When one part of the DNA is unwound the other part is overwound which exerts strain. DNA gyrases introduces negative supercoiling to reduce the strain.
What is the role of Cscl and ethidium bromide in plasmid purification?
The CsCl forms a gradient and the molecules migrate according to their density until they float at their individual isopycnic points (the point in the gradient that equals the buoyant density of the molecule). However, plasmid DNA and contaminating chromosome have about the same density and cannot be separated easily. This is rectified, however, by the addition of ethidium bromide. Density is a function of AT/GC ratio, but it is also a function of conformation. For supercoiled DNA, there is more DNA per unit volume than for relaxed DNA. Intercalation of ethidium bromide into DNA causes the helix to unwind (negative supercoiling) and become more relaxed. However, negative supercoiling only relaxes the DNA to a point. Further unwinding induces supercoiling in the opposite direction. When the DNA is circular and the ends are connected, the plasmid "kinks up" into a very tight knot. Thus, ethidium bromide causes the plasmid density to be increased.
How does DNA make itself more compact?
wrapping tightly around associated proteins
How does ethidium bromide interact with double stranded DNA Does it increase or remove supercoiling?
when ethidium ion intercalates between two dna base pairs in a circular dna it causes the dna to unwind by 26 degrees, thereby decreasing twist and increasing writhe. in a circular dna which is negatively supercoiled, if ethidium is added it will become relaxed and if more ethidium is added dna becomes positively supercoiled
What enzyme can remove or insert super coil twists into circular DNA?
The enzyme topoisomerase is used in inserting or loosing supercoiling in DNA during replication. It is of different type like gyrase, helicase etc. and are found in prokaryotes and eukaryotes respectively
What enzyme is responsible for breaking the hydrogen bonds between the two strands and unwinding the helix?
Helicases and gyrases both function to uncoil the supercoiling of the two DNA strands. Moreover, gyrase is responsible for adjusting the tension in the two strands so that they don't snap while unraveling.
How does all the DNA fit inside your cells?
The DNA molecule has 2 long backbones of phosphates and sugars with bases sticking out are running right next to each other. Then the back bones coil so it will fit into the nucleus. Because the DNA coils is because it contains millions if atoms, DNA has to coil.
