Explain briefly
(a) PCR
(b) Restriction enzymes and DNA
(c) Chitinase
Explain briefly
(a) PCR
(b) Restriction enzymes and DNA
(c) Chitinase
(a) PCR stands for Polymerase Chain Reaction, a method of amplifying fragments of DNA. This method can make multiple copies of even a single DNA fragment or the gene of interest, in a test tube. The reaction mixture requires
(i) Double-stranded DNA fragment (gene of interest).
(ii) Primers-small chemically synthesised oligonucleotides that are complementary to the regions of this DNA.
(iii) The special thermostable DNA polymerase, Taq polymerase (isolated from a bacterium, Thermus aquaticus), that does not denature and remain active even at high temperatures.
The unwinding of two strands of DNA by heating the sample at 92-94∘C helps primers to get positioned on the exposed nucleotides as per base-pairing rules. Taq polymerase recognises primers as 'start' tags and begins to extend the primers using the free nucleotides provided in the reaction and the genomic DNA as the template. With each round of reaction, the DNA doubles.
(b) These enzymes are used in genetic engineering to cut the large DNA molecule into smaller fragments.
When DNA from two different sources are cut by the same restriction enzyme, the resultant DNA fragments have the same kind of 'sticky-ends' and these can be joined together (end-to-end) using DNA ligases.
This new DNA created by joining fragments, from two different sources/genomes together, is recombinant DNA.
(c) Chitinase is an enzyme that breaks down chitin, a component of the fungal cell wall. It is useful for isolating the fungal cell DNA.
(a) PCR stands for Polymerase Chain Reaction, a method of amplifying fragments of DNA. This method can make multiple copies of even a single DNA fragment or the gene of interest, in a test tube. The reaction mixture requires
(i) Double-stranded DNA fragment (gene of interest).
(ii) Primers-small chemically synthesised oligonucleotides that are complementary to the regions of this DNA.
(iii) The special thermostable DNA polymerase, Taq polymerase (isolated from a bacterium, Thermus aquaticus), that does not denature and remain active even at high temperatures.
The unwinding of two strands of DNA by heating the sample at 92-94∘C helps primers to get positioned on the exposed nucleotides as per base-pairing rules. Taq polymerase recognises primers as 'start' tags and begins to extend the primers using the free nucleotides provided in the reaction and the genomic DNA as the template. With each round of reaction, the DNA doubles.
(b) These enzymes are used in genetic engineering to cut the large DNA molecule into smaller fragments.
When DNA from two different sources are cut by the same restriction enzyme, the resultant DNA fragments have the same kind of 'sticky-ends' and these can be joined together (end-to-end) using DNA ligases.
This new DNA created by joining fragments, from two different sources/genomes together, is recombinant DNA.
(c) Chitinase is an enzyme that breaks down chitin, a component of the fungal cell wall. It is useful for isolating the fungal cell DNA.
