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Skip to 0 minutes and 14 seconds We’re going to turn to another important biotechnology and that’s polymerase chain reaction, PCR. It is a very common and often indispensable technique to exponentially amplify the DNA or a gene. The beauty of that is it is an in vitro technique without having to use a living organism such as E. coli or yeast. However, we do need the primers to jumpstart the reaction and the primers must be complementary to the target region or the target DNA. It employs a heat DNA polymerase such as Taq polymerase the enzyme that we talked about last time which is isolated from a thermophilic bacteria. It’s called Thermus Aquaticus. And that’s why it’s called Taq enzyme.

Skip to 1 minute and 18 seconds And depending on the primers used, different DNA’s can be produced. Applications of PCR. It can be used to clone the genes. It can be used to detect and screen infectious disease such as HIV before the symptoms appear. It can be used to detect hereditary disease, or paternity testing. So here I want to remind fellow student, be discretionary and responsible because they’re going to find out who is the father of who is the mother. Forensic medicine that you can duplicate the samples to send to the different site for confirmation. Anthropological identification. You can find out who your ancestors are. And not… Last but not the least, it can be used for basic biological and medical research. PCR procedures. Three steps.

Skip to 2 minutes and 39 seconds Denaturation to produce a single strand DNA and that can be done using heat or adjusting the pH or osmotic pressure. Annealing of the primers to the single-stranded DNA. That’s the second step.

Skip to 2 minutes and 58 seconds And the third step is the polymerization and elongation to the new DNA product. And this is the sketch for the polymerase chain reaction. Here. The first step is denaturation at a higher temperature of 95 degree And annealing of the primer, to the single-stranded DNA which happens at a little bit lower temperature at about 68 and raise the temperature again to 72 degree to elongate and polymerize the template DNA. And now the procedure repeats itself again and we have 4 copies of DNA.

Skip to 3 minutes and 56 seconds And this is the thermal cycling of the PCR procedure. Again. Denaturation, annealing with the primer, and extension with the polymerization. And the exponential growth of the PCR procedures which resulted in literally billions of copies of the gene or the DNA.

Polymerase Chain Reaction

With its revolutionary yet inexpensive biochemical technology, PCR is considered to be one of the most indispensable techniques used in the medical and biochemical research laboratories.

PCR is an in-vitro biotechnological tool, bypassing the need for the use of microorganisms. Essentially three steps are involved denaturation, annealing, and elongation. Its applications include gene cloning, detection of hereditary disease, anthropological identification, and forensic medicine, just to name a few.

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This video is from the free online course:

Pharmacotherapy: Understanding Biotechnology Products

Taipei Medical University