DNA and Genetics

PCR is a technique for amplifying DNA in vitro. It is not a method for transferring DNA into a host cell; methods like microinjection, gene guns, and vectors are used for transformation.

PCR is specifically designed to amplify a specific DNA sequence, producing billions of copies from a small starting amount of template DNA.

Polymerase chain reaction (PCR) is a technique that exponentially amplifies a single copy of a specific DNA segment. It generates thousands of copies of that specific DNA segment. After completion of one cycle, 2 copies are produced from a single DNA segment. After completion of the second cycle, 2$^2$ = 4 copies are produced. Similarly, after n$^{th}$ cycle, 2$^2$ copies are produced, where n is the number of cycles. Hence, after completion of 6 cycle, 2$^6$ = 64 copies will be produced. 

Polymerase Chain Reaction (PCR) is widely used the method in genetic engineering to prepare the multiple copies of desired DNA. It includes steps of denaturation, annealing extension and last amplification. As DNA is the polymer of four DNA bases present in the base pair and polymerase chain reaction is done in the presence of DNA polymerase enzyme of the DNA that re-studies by the researchers which is said to be DNA library so it is not required in the reaction.

A primer is a short single strand of RNA or DNA (generally about 18-22 bases) that serves as a starting point for DNA synthesis. It is required for DNA replication because the enzymes that catalyze this process, DNA polymerases, can only add new nucleotides to an existing strand of DNA. The polymerase starts replication at the 3′-end of the primer, and copies the opposite strand. 

A DNA sequencing reaction was performed with the fragment 5−XXXGCGATCGYYYY−3′ as the template, dideoxy GTP, all the four dNTPs, and the required primers and enzyme. XXXX and YYYY in the given DNA fragment represent primer binding sites. The set of fragments obtained during the reaction will be CGATCGC, because if primer is attache to the XXXX binding site it polymerization starts and its complimentary fragment is CGATCGC.

• Agarose is derived from seaweeds Gelidium and Gracilaria
• Opine synthesis is the function of Ti plasmid of Agrobacterium
• Biolistic is the term used for gene gun used for biotransformation
• Thermocycler is used to carry out PCR reaction

Answer is option C i.e. "Gel electrophoresis"
Gel electrophoresis is the technique which can check DNA fragment progression. Restriction enzyme digest DNA into fragments. Each fragment has different size. When gel electrophoresis is performed each fragment with different sizes are separated on the gel.
While, PCR is used for DNA amplification. Bioreactors are the fermentors used for fermentation process and micro-injection is a method used to transfer genes between animals.

DNA polymerase enzyme synthesizes DNA strands by adding deoxyribonucleotides to 3' end of the primer via phosphodiester bonds; it uses parental DNA as a template. Kary Mullis got Nobel prize, in 1993 in chemistry, for the invention of polymerase chain reaction (PCR).  PCR - technique amplify the gene of interest.

Polymerase chain reaction is a method of amplifying a specific segment of DNA by making multiple copies of it, using primers and DNA polymerase

PCR and RFLP (Restriction Fragment Length Polymorphism) are fundamental tools used in genetic engineering for DNA analysis, cloning, and mapping.

PCR requires primers to define the target region and a DNA polymerase to extend the strands. DNA ligase is not used in PCR.

Taq polymerase is a thermostable DNA polymerase I obtained from the thermophilic bacterium Thermus aquaticus.