Polymerase chain reactions I Biotechnology I CH#23 I Lec# 5 I F.SC. Biology I Class12

#chapter23 #class12biology #F.sc.biology #chapter23biotecnology Like Our facebook page. -----------------------------------   / bismacademy   ------------------------------------ The polymerase Chain Reaction. Kary B. Mullis developed the polymerase chain reaction (PCR) in 1983. Earlier methods of obtaining multiple copies of a specific sequence of DNA were time consuming and expensive. Benefits. Rapid Copier. PCR can create millions of copies of a single gene or any specific piece of DNA quickly in a test tube. Very specific. PCR is very specific - the targeted DNA sequence can be less than one part in a million of the total DNA sample. .This means that a single gene or smaller piece of DNA, among all the human genes can be amplified (copied) using PCR. Reason to Name. PCR takes its name from DNA polymerase, the enzyme that carries out DNA replication in a cell. It is considered a chain reaction because DNA polymerase will carry out replication over and over again, until there are millions of copies of the desired DNA. Limitation. PCR does not replace gene cloning, which is still used whenever a large quantity of gene or protein product is needed. Process. Use of Primer. Before carrying out PCR, primers - sequences of about 20 bases that are complementary to the bases on either side of the “target DNA” - must be available. The primers are needed because DNA polymerase does not start the replication process; it only continues or extends the process. DNA polymerase. After the primers bind by complementary base pairing to the DNA strand, DNA polymerase copies the target DNA. Taq polymerase. DNA polymerase used is temperature - insensitive (thermostable) enzyme extracted from the bacterium Thermus aquaticus, which lives in hot springs. Commonly, this enzyme is also known as Taq polymerase. Importance. It can withstand high temperature, which is used to separate double stranded DNA, therefore, replication need not be interrupted by the need to add more enzyme. Thermorecycler. PCR is done these days in an automatic PCR machine or thermocycler, which is a routine piece of equipment in any laboratory#chapter23 #class12biology #F.sc.biology #chapter23biotecnology Like Our facebook page. -----------------------------------   / bismacademy   ------------------------------------ The polymerase Chain Reaction. Kary B. Mullis developed the polymerase chain reaction (PCR) in 1983. Earlier methods of obtaining multiple copies of a specific sequence of DNA were time consuming and expensive. Benefits. Rapid Copier. PCR can create millions of copies of a single gene or any specific piece of DNA quickly in a test tube. Very specific. PCR is very specific - the targeted DNA sequence can be less than one part in a million of the total DNA sample. .This means that a single gene or smaller piece of DNA, among all the human genes can be amplified (copied) using PCR. Reason to Name. PCR takes its name from DNA polymerase, the enzyme that carries out DNA replication in a cell. It is considered a chain reaction because DNA polymerase will carry out replication over and over again, until there are millions of copies of the desired DNA. Limitation. PCR does not replace gene cloning, which is still used whenever a large quantity of gene or protein product is needed. Process. Use of Primer. Before carrying out PCR, primers - sequences of about 20 bases that are complementary to the bases on either side of the “target DNA” - must be available. The primers are needed because DNA polymerase does not start the replication process; it only continues or extends the process. DNA polymerase. After the primers bind by complementary base pairing to the DNA strand, DNA polymerase copies the target DNA. Taq polymerase. DNA polymerase used is temperature - insensitive (thermostable) enzyme extracted from the bacterium Thermus aquaticus, which lives in hot springs. Commonly, this enzyme is also known as Taq polymerase. Importance. It can withstand high temperature, which is used to separate double stranded DNA, therefore, replication need not be interrupted by the need to add more enzyme. Thermorecycler. PCR is done these days in an automatic PCR machine or thermocycler, which is a routine piece of equipment in any laboratory