Biology Test 34

RNA interference (RNAi) is a biological mechanism which leads to post-transcriptional gene silencing (PTGS) trigger by double-stranded RNA (dsRNA) molecules to prevent the expression of specific genes. RNAi mechanism has the potential in the identification and functional assessment of thousands of genes within any genome that is responsible for crop improvement.RNAi involves binding of a complementary RNA strand to bind to the mRNA molecule to suppress the gene expression.

Bioethics is the ethical problems which is associated with the biological world.

Gene therapy replaces the defective genes for the disorder in embryonic cells thereby curing the disease in all cells of the adult. 1 & 2 can be cures but they are not permanent.

Xenotransplantation is the use of animal cells, tissues and organs. The domestic pig is the optimum donor for such transplants. Pigs are most similar to humans in terms of their development. So the enzymes are also very similar and the biochemical pathways. However, xenogeneic transplantation from pigs to humans involves high immune incompatibility and a complex rejection process. The rapid development of genetic engineering techniques enables genome modifications in pigs that reduce the cross-species immune barrier.

Charles Weissmann (born 14 October 1931) is a Hungarian-born Swiss molecular biologist. Weissmann is particularly known for the first cloning and expression of interferon and his contributions to the unravelling of the molecular genetics of neurogenerative prion diseases such as scrapie, Creutzfeldt–Jakob disease and "mad cow disease".
Weissmann won several awards, including the Otto Warburg Medal (1980) and the Scheele Award (1982). A member of the American Society of Biological Chemistry and the Deutsche Akademie der Naturforscher Leopoldina he is also a Foreign Associate of the U.S. National Academy of Sciences, the Royal Society (UK) and the Pour le Mérite (Germany). On May 16, 2011, Weissmann became Doctor of Science Honoris Causa at New York University.

Both acridine orange and EtBr are useful for staining nucleic acids. 
EtBr is commonly used as visualizing dye in electrophoresis. It is known as the intercalating agent because it intercalates between the nitrogenous bases of DNA and fluorescence under the proper condition. 
Acridine orange interacts with DNA and RNA by intercalation or electrostatic attractions respectively. Is used as a nucleic acid-selective fluorescent cationic dye.

This process is called microinjection. Gene guns are used by which tungsten bullets coated with recombinant DNA are injected into cells for recombinant DNA technology experiments. Microinjection is a different process.

When a gene of interest is inserted into a coding region of a gene, it will lead to inactivation of that gene. Hence it is called insertional inactivation. It acts as a selectable marker.

Polymerization never occurs at such temperatures. High temperature is needed for denaturation step. However, thermos-stable Taq polymerase is used because the denaturation occurs at high temperatures.

In Recombinant DNA Technology, Vectors play a major role in transferring the desirable gene from one organism to another.

• Cloning vector: DNA molecule that can carry foreign DNA into a host cell to replicate it, the original bacterial plasmid. The first vector that was developed for gene cloning was plasmids which are versatile and thus widely used.
• Expression vectors: The expression vector is a plasmid engineered to introduce a particular gene into the target cell. The plasmid contains the regulatory sequences that serve as enhancer and promoter regions needed for the expression of a specific gene using the transcription and translation machinery of the target cell. Example: The plasmid used to produce insulin important for treating diseases such as diabetes.