Presentation on theme: "Polymerase Chain Reaction (PCR)"— Presentation transcript:
1 Polymerase Chain Reaction (PCR) Aims:Must be able to outline the polymerase chain reaction (PCR).Should be able to explain the importance of PCR.Could be able to describe the stages of PCR in datail.
2 DNA AmplificationUsing the technique called polymerase chain reaction (PCR), researchers are able to create vast quantities of DNA identical to trace samples. This process is also known as DNA amplification.Many procedures in DNA technology require substantial amounts of DNA to work with, for example;DNA sequencingDNA profiling/fingerprintingGene cloningTransformationMaking artificial genesSamples from some sources, including those shown here, may be difficult to obtain in any quantity.
3 Steps in the PCR Process Separate StrandsSeparate the target DNA strands by heating at 98°C for 5 minutesThe laboratory process called the polymerase chain reaction or PCR involves the following steps 1-3 each cycle:Repeat for about 25 cyclesRepeat cycle of heating and cooling until enough copies of the target DNA have been produced.Add Reaction MixAdd primers (short RNA strands that provide a starting sequence for DNA replication), nucleotides (A, T, G and C) and DNA polymerase enzyme.IncubateCool to 60°C and incubate for a few minutes. During this time, primers attach to single-stranded DNA. DNA polymerase synthesizes complementary strands.
4 Polymerase Chain Reaction PCR cyclesNo. of target DNA strands1243816532664712825695121010241120481240961381921416 3841532 76865 536171819202122232425Original DNASampleAlthough only three cycles of replication are shown here, following cycles replicate DNA at an exponential rate and can make literally billions of copies in only a few hours.The process of PCR is detailed in the following slide sequence of steps 1-5.Cycle 1Cycle 2Cycle 3
5 The Process of PCR 1 A DNA sample called the target DNA is obtained DNA is denatured (DNA strands are separated) by heating the sample for 5 minutes at 98CPrimers (short strands of mRNA) are annealed (bonded) to the DNAPrimer annealed
6 The Process of PCR 2NucleotidesThe sample is cooled to 60°C. A thermally stable DNA polymerase enzyme binds to the primers on each side of the exposed DNA strand.This enzyme synthesizes a complementary strand of DNA using free nucleotides.NucleotidesAfter one cycle, there are now two copies of the original sample.
7 ActivityAnswer the questions from pages 231 and 251/2 in the Biozone books.