KA2- PCR Flashcards
What does PCR stand for?
Polymerase chain reaction
What does PCR use DNA polymerase for?
Replicate a DNA molecule to make many copies
Where does PCR take place?
In vitro
What does PCR use? (This isn’t a DNA polymerase question)
Complementary primers for a specific target sequence
What are these complementary primers able to do?
Very precisely located this specific target sequence amid a massive number of other sequences
What is the first step of PCR?
Heating DNA to 92-98° to break hydrogen bonds and separate the two strands
Why in the 1st step of PCR is DNA heated to 92-98°?
To break the weak hydrogen bonds and separate the 2 strands
What is the second step of PCR?
Cooling the separated strands between 50-65°.
Cooling allows primers to bind to target sequences
What does cooling allow?
Primers to bind to target sequences
What is the 3rd step of PCR?
DNA is replicated. Heated between 70-80°
Heat tolerant DNA polymerase replicates the DNA by adding free nucleotides to the 3’ end
What is a thermal cycler?
A specialised water bath that can rapidly raise and lower the temperature
What does repeated cycles of heating and cooling do?
Amplifies DNA exponentially so that it can be used for medical and forensic purposes
What can PCR be used to produce?
Millions of copies of a specific piece of DNA in a few hours
Medical uses of PCR
Diagnose a disease
Estimate the risk of disease
What do forensics use PCR for?
Amplify tiny DNA samples from a crime scene; blood, saliva
