Thursday, September 26, 2019

Molecular and ellular Biology Essay Example | Topics and Well Written Essays - 2500 words

Molecular and ellular Biology - Essay Example Genes may be incorporated into bacteria, plants or animals. In this process recombinant DNA (rDNA) technology is used to incorporate gene of interest into organisms and that organism in which gene is inserted is said to be genetically engineered. Through this process off springs with unique characters are produced. Recombinant DNA is also referred to as Chimera. By the combination of two different strands of DNA a new strand of DNA is obtained. The first step in genetic engineering involved the production of hormone insulin which is important and helps the cells to properly absorb sugar. In recombinant DNA technology recombinant DNA is made by splicing a small fragment of a foreign DNA into a small molecule that can replicate on its own such as bacterial plasmid as a result a clone of inserted DNA can be obtained. AN organism that receives a foreign DNA is called transgenic organism and these organisms can be used in research or in commercial applications such as production of human insulin in transgenic bacteria (which receives genes from human responsible for the production of insulin). This application gives the idea that how important DNA recombinant technology is.(Recombinant DNA technology). Two classes of enzymes play an important role in DNA recombinant technology. Restriction endonucleases: They recognize specific sites on DNA and cleave DNA at that site into smaller fragments. DNA ligases: They link the foreign DNA with the vector DNA. Cloning of DNA involves the following steps: 1: First step in making recombinant DNA is to isolate donor and vector DNA. 2: Cloning vector is cleaved with restriction endonucleases. 3: gene of interest is obtained by cleaving chromosome of foreign DNA with the same restriction endonuclease into smaller fragments. 4: Fragments are ligated to the cloning vector by DNA ligase as a result a recombinant vector is obtained. 5: This recombinant DNA is introduced into the host cell where it replicates and produces copies of recombinant DNA. (Lehninger, Principles of Biochemistry fourth edition). Recombinant DNA technology in the synthesis of insulin: Insulin is an important hormone which regulates the storage of carbohydrates in the body. It is secreted by the beta cells present in the pancreas islets of langerhans. Insulin is a small protein and is composed of two polypeptide chains which are linked together by disulfide bonds. When blood glucose level is high insulin is secreted into the blood stream and removes excess of glucose from the body. Human insulin is the only known protein which can be produced in bacteria by DNA recombinant technology in a way that its structure and composition resembles the original molecule. In diabetes patients problems are associated with the production of insulin due to which sugar increases to dangerous levels which could be life threatening. These patients are treated with insulin which is produced in another organism. Although insulin can be produced in animals whose insulin resembles human insulin in terms of composition with minor variations like bovine and porcine insulin but, it was observed that when bovine and porcine insulin were injected into the patient’s body antibodies were produced against them thereby, neutralizing it’s action and producing inflammatory response at the site of injection. These problems suggest that a suitable vector like E.coli could be used to produce insulin. E.coli is a common inhabi tant of the human digestive tract and is a key organism used in the production of insulin by genetic engineering. Following are the steps involved in the production of insulin from a bacterial host. 1: Isolate gene: The gene that produces insulin in human is isolated and is

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