Genetic Engineering and Recombinant DNA Technology

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. 

Golden rice is a genetically modified variety of rice engineered to produce beta-carotene, which the body converts into vitamin A.

Genetic engineering mainly aims at the transfer of genes of desired protein products between the organisms. Plastids are double membrane bound organelles that serve as the site for photosynthesis. Mitochondria are double membrane bound eukaryotic cell organelles that serve as the site for cellular respiration, produce an enormous amount of energy. ER is eukaryotic organelle with a network of tubules, vesicles, and cisternae within the cells. It serves to synthesis and transport of proteins and lipids. Plasmids are low molecular weight extrachromosomal DNA that carries origin of replication, restriction sites and selectable markers to confer readily selectable phenotypic traits on host cells. Plasmids require very few genes for their own replication and rest of it can be deleted and foreign sequences can be added to the plasmid which in turn makes them a suitable candidate to serve as a vector for gene transfer. Thus, the correct answer is option A.

Genetic engineering mainly aims at the transfer of genes of desired protein products between the organisms. Lysosomes are the suicidal bags of cell that digest and remove the wear and tear organelles and molecules from the cell. Golgi body consist of flattened sacs stacked on each other, that serve to processes secretory and synthetic products from the ER and then transport the finished products into cell part or secretes them to the outside of the cell. Mitochondria are double membrane bound eukaryotic cell organelles that serve as the site for cellular respiration, produce an enormous amount of energy and therefore are also known as a power house of cell. Plasmids are low molecular weight extrachromosomal DNA that carries origin of replication, restriction sites and selectable markers to confer readily selectable phenotypic traits on host cells. Plasmids require very few genes for their own replication and rest of it can be deleted and foreign sequences can be added to the plasmid which in turn makes them a suitable candidate to serve as a vector for gene transfer. Thus, the correct answer is option C.

Genetically engineered insulin is sold with commercial name 'humulin'.

Terminator seeds are hybrid seeds that germinate and grow normally but produce sterile seeds in the next generation, preventing farmers from saving seeds. They do not produce flog-terminable seeds or incompatible gametes. The high yield claim is secondary to their terminator characteristic.

Genetic engineering allows for the production of various therapeutic proteins, including calcitonin, growth factors, and erythropoietin, using recombinant DNA technology.

Alpha-1 antitrypsin is a protein used to treat emphysema, a condition where the lungs are damaged, by inhibiting the enzyme elastase.

Transgenic hirudin is obtained from Brassica napus.

• Several animal studies indicate serious health risks associated with genetically modified (GM) food including infertility, immune problems, accelerated aging, faulty insulin regulation, and changes in major organs and the gastrointestinal system.
  
• One of the first cases of human benefit from genetic engineering was the production of human insulin in bacterial cells. Previous to this, diabetic patients were treated with pig insulin. Use of bacterially-derived human insulin has substantially reduced the number of animals used to produce insulin and also significantly reduces adverse reactions in diabetic patients as the molecule is identical to human insulin. Since the successful production of genetically engineered insulin, many other human proteins have been produced in this manner. This technology has improved millions of lives.
  

Genetic engineering is a technique to alter the chemistry of genetic material (DNA and RNA), to introduce these into the host organisms and thus change the phenotype and genetic makeup of the organism.

Cloning is the process of generating a genetically identical copy of a cell or an organism. Cloning happens all the time in nature for example, when a cell replicates itself asexually without any genetic alteration or recombination.

The first transgenic cow, Rosie was engineered for production of human protein-enriched more nutritional balanced milk (2.4 grams per litre). Rosie’s milk contains the human gene $\alpha$-lactalbumin; which makes statement A incorrect. Transgenic bull was produced for lactoferrin in their milk which has antimicrobial activity and is components of innate defence; statement B is incorrect. Animal rabbit models have been used to study pathophysiology and treatment of cardiovascular diseases which makes statement D correct. Transgenic mice for testing safety of polio vaccine before use in human; for the purpose, they are subject to GSK test which measures the safety of the vaccine; statement C is correct.

Genetic engineering is the specific technology used to isolate, modify, and transfer genes between different organisms.

A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules. Plasmids carry only a few genes and exist independently of chromosomes, the primary structures that contain DNA in cells. Able to self-replicate, plasmids can be picked up from the environment and transferred between bacteria. Plasmids are used by their host organism to cope with stress-related conditions.

Genetic engineering is the process of manually adding new DNA to an organism. The goal is to add one or more new traits that are not already found in that organism. Examples of genetically engineered (transgenic) organisms currently on the market include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. 

A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. These enzymes are found in bacteria and archaea and provide a defense mechanism against invading viruses. Inside a prokaryote, the restriction enzymes selectively cut up foreign DNA in a process called restriction; while host DNA is protected by a modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage. Together, these two processes form the restriction modification system. These enzymes are routinely used for DNA modification in laboratories, and are a vital tool in molecular cloning.

A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. These enzymes are found in bacteria and archaea and provide a defense mechanism against invading viruses. Inside a prokaryote, the restriction enzymes selectively cut up foreign DNA in a process called restriction; while host DNA is protected by a modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage. Together, these two processes form the restriction-modification system. These enzymes are routinely used for DNA modification in laboratories and are a vital tool in molecular cloning.

In molecular cloning, a vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed. A vector containing foreign DNA is termed recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids. 

Genetic engineering, also called as genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species to produce improved or novel organisms. 

Genetic engineering, also called as genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species to produce improved or novel organisms. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. 

Recombinant DNA (or rDNA) is made by combining DNA from two or more sources. In practice, the process often involves combining the DNA of different organisms. The process depends on the ability to cut and re-join DNA molecules at points which are identified by specific sequences of nucleotide bases called restriction sites. DNA fragments are cut out of their normal position in the chromosome using restriction enzymes (also called restriction endonucleases) and then inserted into other chromosomes or DNA molecules using enzymes called ligases.

In molecular cloning, a vector is a DNA molecule used as a vehicle or carrier which carries the desired gene from donor to recipient cell, where it can be replicated and/or expressed. The plasmid is extrachromosomal circular DNA which acts as vector DNA. The plasmid is the most important vector as it possesses multiple cloning sites, an origin of replication and a selectable marker.

The production of a recombined bacterium using a gene from a foreign donor and the synthesis of a protein encoded by the recombinant DNA molecule. The genes used as a donor in recombinant DNA technology are commonly obtained from bacteria, yeast or any eukaryotic host organism. 

In molecular cloning, a vector is a DNA molecule used as a transport to artificially carry foreign genetic material into another cell, where it can be replicated and expressed. A vector containing foreign DNA is termed recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids.