PCR Flashcards
what does PCR stand for?
polymerase chain reaction
describe PCR?
= taking DNA or section of it and making more and more copies of it so you have lots of copies to sequence and analyse
what is a PCR machine?
- thermal cycler
- able to increase heat then decrease it again
what are the 4 key ingredients?
DNA sample
primer
nucleotides
Taq polymerase
describe the DNA sample
section of DNA we want more copies of
describe primer
copies of snippets of DNA that act as markers to show where we want to sequence the DNA
describe nucleotides
normal free nucleotides to make copies with
describe Taq polymerase
human DNA polymerase is replaced with more heat-stable taw polymerase that comes from bacteria
why is Taq polymerase used over DNA polymerase?
workers better and faster at higher temperatures
what is PCR used for?
- make extra DNA
- identify genetic diseases
- identify viral disease
what is the first step of the PCR process?
denaturing = 94 degrees
- double-stranded DNA melts open into two pieces of single-stranded DNA
- all enzyme reactions stop
what is the second step of the PCR process?
annealing = 54 degrees
- primers = custom-made, short single strands of DNA
- primers are designed specially to bond to sites at the beginning and end of the segment to be copied
- primers pair up with the single-stranded template of DNA
what is the third step of the PCR process?
extension = 72 degrees
- ideal temp for Taq polymerase
- polymerase copies DNA by rapidly joining complementary bases to the template DNA strand
what are the 3 steps of the PCR process and their temperatures?
1) denaturing = 94 degrees
2) annealing = 54 degrees
3) extension = 72 degrees
