Qualitative analysis of group 2 cations flow chart - all
Boron is a chemical element with the symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis , it is a low-abundance element in the Solar System and in the Earth's crust. These are mined industrially as evaporites , such as borax and kernite. The largest known boron deposits are in Turkey , the largest producer of boron minerals. Elemental boron is a metalloid that is found in small amounts in meteoroids but chemically uncombined boron is not otherwise found naturally on Earth. Industrially, very pure boron is produced with difficulty because of refractory contamination by carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard about 9. The primary use of elemental boron is as boron filaments with applications similar to carbon fibers in some high-strength materials. Boron is primarily used in chemical compounds. About half of all boron consumed globally is an additive in fiberglass for insulation and structural materials. qualitative analysis of group 2 cations flow chartPolymerase chain reaction PCR is a method widely used to rapidly make millions to billions of copies of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it to a large enough amount to study in detail.
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It is fundamental to much of genetic testing including analysis of ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research and criminal forensics. The majority of PCR methods rely on thermal cycling. Thermal cycling exposes reactants to repeated cycles of heating and cooling to permit different temperature-dependent reactions — specifically, DNA melting and enzyme -driven DNA replication.
In the first step of PCR, the two strands of the DNA double helix are physically separated at a high temperature in a process called nucleic acid denaturation.
In the second step, the temperature is lowered and the primers bind to the complementary sequences analysiis DNA. As PCR progresses, the DNA generated is itself used as a template for replication, setting in motion a chain reaction in which the original DNA template is exponentially amplified.
Almost all PCR applications employ a heat-stable DNA polymerase, such as Taq polymerasean enzyme originally isolated from the thermophilic bacterium Thermus aquaticus.
Broup the polymerase used was heat-susceptible, it would denature under the high temperatures of the denaturation step. Before the use of Taq polymerase, DNA polymerase had to be manually added every cycle, which was a tedious and costly process. Applications of the technique include DNA cloning for sequencinggene cloning and manipulation, gene mutagenesis; construction of DNA-based phylogeniesor functional analysis of genes ; diagnosis and monitoring of hereditary diseases ; amplification of ancient DNA; [4] analysis of genetic fingerprints for DNA profiling for example, in forensic science and parentage testing ; and detection of pathogens in nucleic acid tests for the diagnosis of infectious diseases. A basic PCR set-up requires several components and reagents, [7] including:. The thermal cycler heats and cools the reaction tubes to achieve the temperatures required at each step of the reaction see below.
Many modern thermal cyclers make use of the Peltier effectwhich permits both heating and cooling of the block holding the PCR tubes simply by reversing the electric current. Thin-walled reaction tubes permit favorable thermal conductivity to allow for rapid thermal equilibrium.]
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