Genetic engineering restriction enzymes

The polymerase chain reaction (PCR) is an important procedure in genetic engineering that allows any DNA segment to be replicated (amplified) without the need for restriction enzymes, vectors, or host cells (see p. 258). However, the nucleotide sequence of the segment has to be known. Two oligonucleotides (primers) are needed, which each hybridize with one of the strands at each end of the DNA segment to be amplified also needed are sufficient quantities of the four deoxyribonucleo-side triphosphates and a special heat-tolerant DNA polymerase. The primers are produced by chemical synthesis, and the polymerase is obtained from thermostable bacteria. 

Enzymes, specialized proteins, are used as designing tools for genetic engineering. One of these enzyme tools consists of restriction endonucleases that recognize a specific series of base pairs. They split the DNA at these specific points. This splitting is called lysing , which in reality is simply the hydrolysis of DNA units as shown in the following structure ... 

The restriction enzymes and hybridomas enabled new types of pharmaceutical products The developments associated with restriction enzymes (facilitate genetic engineering) and hybridomas (produce monoclonal antibodies) opened up vistas for a new range of potential products. Isolated from humans directly, these can now be produced in microorganisms or cell culture, and be used in large concentrations to enhance the body s ability to fight heart disease, cancer, and viral infections against which most antibiotics have little or no effect. 

DNA ligase repairs broken DNA by joining two nucleotides in a DNA strand. It is commonly used in genetic engineering to do the reverse of a restriction enzyme that is, to join together complementary restriction fragments. While sticky ends allow two complementary restriction... 

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