Tag: biotechnology and genetic engineering

Genetic engineering is the technique by which the genetic material of an organism is manipulated. The desired genes from any organism are isolated and are transferred into the organism where those genes are expressed and desired products are obtained. Manipulation of an organism's genome is not a simple process and involves a number of tools including restriction enzymes. 

Answer is option C i.e. "The same enzyme that cleaves the donor DNA"
In rDNA technology, the plasmid vector must be cleaved by specific restriction enzyme. Plasmid vectors are cleaved by  same enzyme that cleaves the donor DNA leading to creation of sticky ends which further helps in recombination.

Answer is option D i.e. "GMO"
GMO are genetically modified organism. GMOs are every plant, animal, or microorganism that is transformed by genetic engineering. Tools of genetic engineering are the requirements to carry in-vitro genetic engineering process, this involves the use of laboratory tools to insert, alter, or cut out pieces of foreign DNA with help of restriction enzyme and cloning them through vector in respective host cell.

The non-mutated normal form of a gene which is naturally present in population is called as wild type allele. They impart natural genotype and natural phenotypes/traits to the organisms which is not a target for genetic engineering. Defective genes are the one that code for non-working or malfunctioning polypeptide and, thus, adversely affect the organisms. These genes should be eliminated, not preserved, from genome to fix the defects caused by them. Gene therapy is the process of introduction of DNA into living human beings in order to treat disease. It is used to replace a missing gene product or to correct mutant alleles. Gene therapy is a type of genetic engineering.

• Bioprocess engineering is a type of chemical engineering, it is responsible for the development of materials that are used in biotechnology like food, chemicals, tools etc.
  
• Genetic engineering also involves chemical as well as biological engineering, This technique involves the manipulation of DNA, its constituents to make a desirable DNA.
• Maintenance of ambiance means to maintain a microbial or disease-free culture for the process of biotechnological techniques so that only the desired gene or cell is amplified (multiplication of gene to form a large number of copies).

Xanthomonas is used for bioproduction of xanthan gum which is a polysaccharide and is used as a food additive. Bacillus thuringiensis (Bt) produces Bt toxin during sporulation. The toxin bind to receptors on midgut epithelial cells of gallworm, become inserted into the plasma membrane where they form pores leading to cell death through osmotic lysis; thus serving as biopesticide. Trichoderma serve as very effective biocontrolling agent for soil borne plant disease management. It is a free-living fungus, and reduces pathogenic infections by different mechanisms like competition, antibiosis, hyphal interactions, mycoparasitism, , and enzyme secretion. Pseudomonas putida is used in bioremediation owing to its aerobic metabolism with ability to degrade organic pollutants such as toluene and to convert styrene oil to biodegradable plastic Polyhydroxyalkanoates (PHA). Correct answer is A.

Gene synthesis is process to synthesize gene; the gene, for which nucleotide sequence is known, can be synthesized chemically and the genes for which sequencing has not been done, are synthesized by RNA dependent DNA polymerase. The synthesized gene is inserted into genome of selected crop plants which in turn produce the desired protein product; once cloned, genetically engineered crops are economic method of production modified crop plants. GM products are not tasteless; gene for additional taste can be cloned. To achieve desired level of protein products; introduced gene is expressed at higher level which in turn may introduce the antigens/toxins or even viruses in human. Presence of foreign DNA /gene or gene products in crop plants is sensed by immune system of human and can initiate allergic or immune responses in them. Correct option is D.

H. G. Khorana and co-workers synthesized the gene for $E$.$coli$ tyrosine tRNA precursor. The tyrosine tRNA precursor has 126 nucleotides. A complete sequence of dsDNA coding for tyrosine tRNA precursor of E. coli was synthesized. Twenty six small oligonucleotide DNA segments that produced a complete tRNA precursor were synthesized. These oligonucleotides were then arranged into six dsDNA segments. Each ds DNA segment had single stranded ends to facilitate their joining to produce complete gene of 126 base pairs for tyrosine tRNA precursor of E. coli. He then synthesized biologically functional gene coding for tyrosine t-RNA of E.coil. It was 207 base pairs long with 51 bp long promoter region, a 126 bp long precursor region of tRNA, a 25 bp long DNA in which 16 base pairs contained restriction site for EcoRI. Option D is the correct answer.

Agrobacterium tumefaciens is a soil plant pathogenic bacterium that carries Ti plasmid. It can transfer a particular segment of the tumor-inducing (Ti) plasmid into the nucleus of infected cells. The transferred T-DNA is then integrated into the host genome and transcribed with it. This ability of Agrobacterium tumefaciens to transfer the T-DNA in host genome is explored in genetic engineering to transfer the desired DNA segment, carrying the gene of the interest, into genome of selected organisms. Bacillus coagulans is a lactic-acid producing, endospore forming soil bacteria that is used as probiotics. Clostridium septicum is gram positive, spore forming, obligate anaerobic bacteria that cause gas gangrene and is associated with malignancy.