3.13 - PCR Polymerase Chain Reaction Flashcards
1
Q
What does PCR stand for?
A
Polymerase chain reaction
2
Q
What is the purpose of PCR?
A
To start off with a small sample of DNA and force it to replicate, in order to increase the overall amount of DNA to work with
3
Q
What are the 5 steps of doing PCR?
A
1) Prepare the sample
2) Denaturation/ Heating to 95° C
3) Annealing/ Cooling to 55° C
4) Extention/ Heating to 72° C
5) Repitition
4
Q
How do you prepare a PCR test?
What initally goes into the test tube?
A
- the original DNA sample
- a primer known to be complenetary to the side of DNA you wish to replicate (made of DNA not RNA)
- TAQ Polymerase: a version of DNA polymerase found in bacteria that is known to survive hot temperatures
- free nucleotides/ nitrogen bases
5
Q
In PCR…
What happens during denaturation (the 2nd step)?
A
- The tube is heated to 95°
- the double helix seperates into single strands
- the H-bonds holding the nucleotides together break
6
Q
In PCR…
What happens during annealing (the 3rd step)?
A
- The temp is lowered to 55°
- this is the ideal temp because it’s still hot enough to keep strands seperated, but cool enough so that it allows primers to attach
7
Q
In PCR…
What happens during Extension (the 4th step)?
A
- The temp is raised to 72°
- TAQ Polymerase activates at this temperature
- It begins to add the free nucleotides, starting at the primers, to replicate the strands
8
Q
What is targested PCR?
A
- when specific primers are added to a sequence
- scientisits roughly know where the specific primers are going to land.
- Whatever is between the primers is going to be copied
9
Q
Is it possible to replicate all the genes in a cell?
A
No, it is notpossible
