Tag: gene cloning

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. 

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'.

Radiology is a medical specialty that uses imaging to diagnose and treat disease seen within the body. Radiologists use a variety of imaging techniques such as X-ray radiography, ultrasound, computed tomography (CT), nuclear medicine, positron emission tomography (PET) and magnetic resonance imaging (MRI) to diagnose or treat diseases.