BioTechnology Essay
October 3, 2013
Bio Tech Essay
Restriction enzymes are named according to the organism that they are kept in. The way that they create the name is to use the first letter of the genus, and after the first two letters of the species. There are only a certain amount of strains, sub-strains of a certain species that can produce restriction enzymes. A roman-numeral is always used to show one out of possible several different restriction enzymes created by the same organism or by different sub-trains of that same strain. A restriction enzyme requires a specific double-strand recognition sequence of nucleotides to cut DNA. (usually 4-8 base pairs in lengths) Cleavage happens within or near the site; its positions are usually pointed out with arrows. Recognition sites are mostly symmetrical. When DNA strands in the site have the same base sequence are called palindromes. The Recognition sites of some restriction enzymes contain variable base positions. There are 625 possible sequences in a BgI can cleave. In a BgI, recognition bases must always be separated by 5 base pairs of DNA, otherwise the enzyme can’t interact with the DNA and cleave it. These sites are an example of hyphenated sites. The longer the DNA molecule, the greater of a possibility that a given recognition site will occur. That’s why human chromosomal DNA (contains three billion base pairs) has many more recognition sites than a plasmid DNA. (plasmid DNA have only several thousand base pairs. Large DNA is extremely difficult to isolate intact, therefore during handling it is randomly sheared to fragments in the range between 50,000-100,000. Plasmids and several viral DNAs, are circular molecules. If a circular DNA contains one recognition site for one restriction enzyme, than it will open to form a linear DNA molecule. If a linear
DNA molecule contains a single recognition site, then when cleaved it will generate two fragments. The sizes of these fragments depend on how far the
Bio Tech Essay
Restriction enzymes are named according to the organism that they are kept in. The way that they create the name is to use the first letter of the genus, and after the first two letters of the species. There are only a certain amount of strains, sub-strains of a certain species that can produce restriction enzymes. A roman-numeral is always used to show one out of possible several different restriction enzymes created by the same organism or by different sub-trains of that same strain. A restriction enzyme requires a specific double-strand recognition sequence of nucleotides to cut DNA. (usually 4-8 base pairs in lengths) Cleavage happens within or near the site; its positions are usually pointed out with arrows. Recognition sites are mostly symmetrical. When DNA strands in the site have the same base sequence are called palindromes. The Recognition sites of some restriction enzymes contain variable base positions. There are 625 possible sequences in a BgI can cleave. In a BgI, recognition bases must always be separated by 5 base pairs of DNA, otherwise the enzyme can’t interact with the DNA and cleave it. These sites are an example of hyphenated sites. The longer the DNA molecule, the greater of a possibility that a given recognition site will occur. That’s why human chromosomal DNA (contains three billion base pairs) has many more recognition sites than a plasmid DNA. (plasmid DNA have only several thousand base pairs. Large DNA is extremely difficult to isolate intact, therefore during handling it is randomly sheared to fragments in the range between 50,000-100,000. Plasmids and several viral DNAs, are circular molecules. If a circular DNA contains one recognition site for one restriction enzyme, than it will open to form a linear DNA molecule. If a linear
DNA molecule contains a single recognition site, then when cleaved it will generate two fragments. The sizes of these fragments depend on how far the