BIOTECHNOLOGY:
PRINCIPLES AND
PROCESS
Polymerase Chain Reaction(PCR)
The Polymerase chain reaction (PCR) was originally developed in 1983 by the
American biochemist Kary Mullis. He was awarded the Nobel Prize in chemistry in
1993 for his pioneering work. PCR is used in molecular biology to make many
copies of (amplify) small sections of DNA or a gene. Using PCR it is possible to
generate thousands to millions of copies of a particular section of DNA from a
very small amount of DNA. PCR is a common tool used in medical and biological
research labs. It is used in the early stages of processing DNA for sequencing, for
detecting the of presence or absence of a gene, to help identify pathogens during
infection, and when generating forensic DNA profile from tiny samples of DNA.
How does PCR works?
The principles behind every PCR whatever the sample of DNA, are the same. Five
core ingredients are required to set up a PCR, they are:
• the DNA template to be copied.
•Primers, short structures of DNA that initiate the PCR reaction, designed to bind
either side of the section of DNA you want to copy.
•DNA nucleotide bases, also known as (dNTPs). DNA bases (A, C, G and T) are the
building blocks of DNA and are needed to construct the new strand of DNA.
• Taq polymerase enzyme, to add in the new DNA bases.
•Buffer, to ensure the right conditions for the reaction.
, PCR involves a process of heating and cooling called a thermal cycling which is
carried out by machine.
There are three main stages:
1. Denaturing - when the double stranded template DNA is heated it separate
it into two single strands.
2. Annealing - when the temperature is lowered to enable the DNA
primers to attached to the template DNA.
3. Extending - when the temperature is raised and the new strand of
DNA is made by the Taq polymerase enzyme.
These three stages are repeated 20-4o times, doubling the number of DNA copies
each time. A complete PCR reaction can be performed in a few hours, or even less
than an hour with certain high speed machines. After PCR has been completed a
method called Electrophoresis can be used to check the quantity and size of the
DNA fragments produced.
PRINCIPLES AND
PROCESS
Polymerase Chain Reaction(PCR)
The Polymerase chain reaction (PCR) was originally developed in 1983 by the
American biochemist Kary Mullis. He was awarded the Nobel Prize in chemistry in
1993 for his pioneering work. PCR is used in molecular biology to make many
copies of (amplify) small sections of DNA or a gene. Using PCR it is possible to
generate thousands to millions of copies of a particular section of DNA from a
very small amount of DNA. PCR is a common tool used in medical and biological
research labs. It is used in the early stages of processing DNA for sequencing, for
detecting the of presence or absence of a gene, to help identify pathogens during
infection, and when generating forensic DNA profile from tiny samples of DNA.
How does PCR works?
The principles behind every PCR whatever the sample of DNA, are the same. Five
core ingredients are required to set up a PCR, they are:
• the DNA template to be copied.
•Primers, short structures of DNA that initiate the PCR reaction, designed to bind
either side of the section of DNA you want to copy.
•DNA nucleotide bases, also known as (dNTPs). DNA bases (A, C, G and T) are the
building blocks of DNA and are needed to construct the new strand of DNA.
• Taq polymerase enzyme, to add in the new DNA bases.
•Buffer, to ensure the right conditions for the reaction.
, PCR involves a process of heating and cooling called a thermal cycling which is
carried out by machine.
There are three main stages:
1. Denaturing - when the double stranded template DNA is heated it separate
it into two single strands.
2. Annealing - when the temperature is lowered to enable the DNA
primers to attached to the template DNA.
3. Extending - when the temperature is raised and the new strand of
DNA is made by the Taq polymerase enzyme.
These three stages are repeated 20-4o times, doubling the number of DNA copies
each time. A complete PCR reaction can be performed in a few hours, or even less
than an hour with certain high speed machines. After PCR has been completed a
method called Electrophoresis can be used to check the quantity and size of the
DNA fragments produced.
