Polymerase Chain Reaction Flashcards
What does PCR do?
Amplifies one sample of DNA thousands of times over to create a large enough sample of DNA for extensive analysis.
Describe the function of DNA polymerase in the PCR.
Joins together thousands of nucleotides rapidly.
What are primers?
Short sequences of nucleotides that have a set of bases complementary to the end of DNA fragments.
Why is DNA polymerase used in PCR taken from bacteria that live in hot springs?
They are tolerant to heat so the enzyme wont denature
What is a thermocycler?
A computer controlled machine that varies temperature precisely over set periods.
What 3 things are placed in a thermocycler?
DNA fragments, primers, DNA polymerase
What temperature is the thermocycler raised to as the DNA is being split?
96 C
Describe how DNA is split in a thermocycler.
DNA strands between the fragment break as the hydrogen bonds are broken
What does anneal mean?
To stick
Describe the annealing process that occurs during PCR.
Primers bind to the separated strands of DNA.
What temperature is the thermocycler cooled to during the annealing process?
55C
What 2 do primers do after annealing has taken place?
They provide the starting sequence for DNA polymerase to bind to and begin copying.
They also prevent the 2 separate strands from re-joining.
During DNA synthesis, what temperature is the thermocycler raised to?
72C
Describe how DNA polymerase leads to production of new DNA.
DNA polymerase binds to the primers and moves along the strand, joining complementary bases and forming the DNA
How much DNA will be present after a cycle of PCR has taken place compared to at the start?
Double
