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STAIN | DEFINITIONS | PREPARATION | USES

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STAIN | DEFINITION | PREPARATION | USES Staining means the use of dyes to render various tissue constituents variable and distinct from one another. Different parts of cells or tissue react differently to colours due to their chemical and or physical differences. Thus they become easily visible. The preparation, experimenting and uses of stains form a separate science in itself.  The now widely accepted theory of staining is the view advanced by Witt (1876). The presence of colour in a chemical is by the presence of groups or radicals called chromophors. The material that contains these are called chromogens. The power of imparting this colour to other substances is given to a Christian by the presence of an automotive. Auxochrome are either acid or alkali radicals, which also are responsible for solubility of stains.  There are many ways in which a colour may be caused to remain on a particular structure.  The ionized stain becomes precipitated upon mate...
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RESTRICTION ENZYMES

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RESTRICTION ENZYMES Restriction enzymes are help in cutting of DNA into smaller fragments. Different restriction enzymes acknowledge and cut different DNA sequences. Restriction enzymes are also known as molecular scissor.  WHERE DO RESTRICTION ENZYMES COME FROM?  Restriction enzymes are found in bacteria. Bacteria use restriction enzymes to kill viruses the enzyme attack the viral DNA and break it into useless fragments.  HOW DO RESTRICTION ENZYMES WORK?  Restriction enzymes works by shape matching, when it comes into contact with DNA sequences with a shape, that matches a part of the enzyme, called DNA sequences, it wraps around the DNA and causes a break in both strands of the DNA molecule.  Each restriction enzymes recognises a different and specific recognition site,  or DNA sequences. Recognition sites are usually only short 4-8 nucleotides. WHEN ARE RESTRICTION ENZYMES ARE USED?  Restriction enzymes are a basic tool...
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