PCR in the laboratory

In order to prepare a DNA solution for PCR, Tasha needs to add the following ingredients: the DNA molecule to be copied, the enzyme (called Taq polymerase), DNA nucleotides (which will be joined together to make new DNA copies), and RNA primers.
The ingredients are added together and mixed in a buffer solution. The buffer keeps the pH of the whole solution constant (enzymes only work within specific pH ranges).

Transcript

Clare Eagleton

We are going to do PCR today and it is quite abstract because you load all of the reagents into the tube and then you stick it into the machine.

Narrator

Tasha is adding the main reagents. She adds two different primers which are needed to make a copy of a specific region of DNA. A separate solution containing individual nucleotides is also added. These will be used in building the new DNA strands. Clare is now adding Taq polymerase which is the enzyme that will make the new DNA strands. The solution which now contains the enzyme, buffer, primers and free nucleotides is added to a 96 well plate that can be put into the PCR machine. Once the reagents are in the machine, the temperature is increased. This seperates the DNA double helix into two strands. New DNA is made to match each of the original DNA strains. The reaction is cycled through three temperatures and is repeated many times.