Tag: applications of biotechnology

Translation is the process of synthesis of protein using mRNA nucleotide sequence as template, it occurs in cytoplasm. Transcription is the process of mRNA synthesis using DNA coding strand as template, it occurs in nucleus. PCR is a technique to amplify the gene of interest in three steps namely denaturation of target DNA (thermal cycle to separate the DNA strands), annealing of primers to the ssDNA and polymerisation (extension of primer into complete DNA strand complementary to the template strand). After completion of one cycle of PCR, two copies of the target DNA are produced both of which serve as template for next PCR cycle and produce 4 copies. Hence, there is exponential amplification of DNA copies. Correct option is C.

Polymerase chain reaction (PCR) is a method widely used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy (or more) of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment.

DNA polymerase enzyme was isolated from a thermophilc bacteria called Thermus aquaticus. This is an enzyme used frequently to make multiple copies of segment of DNA by a technique called polymerase chain reaction.

The denaturation stage of PCR takes about 1–2 minutes. The thermocycler then lowers the temperature to about 50° to 60°C, which allows the short, oligonucleotide primers to anneal to their complementary sequences on the single-stranded DNA molecules. The annealing stage of PCR lasts about 30 seconds. Hence, the whole cycle of gene amplification requires 30 minutes.

PCR requires a thermostable DNA polymerase to synthesize new DNA strands during the extension phase. Taq polymerase, isolated from Thermus aquaticus, is the standard enzyme used because it withstands high temperatures.

A thermal cycler is an instrument used to perform PCR by precisely controlling the temperature changes required for denaturation, annealing, and extension.

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.