bio 4C Flashcards
Polymerase chain reaction
what is PCR
a laboratory technique used to produce many identical copies of DNA from a small initial sample (after every PCR, the DNA sample is doubled + uses primers and restriction endonuclease)
what is the ‘denaturation’ step of PCR
the DNA sample is heated and denatured (heated to approx. 90-95°c to break the weak hydrogen bonds between the strands)
what is the ‘annealing’ step of PCR
the DNA is cooled to approx. 50-55°c so that the sequence-specific DNA primers can join the 3’ end of the single-stranded DNA by CBP to form the first segment of double-stranded DNA which allows Taq polymerase to attach
what is the ‘elongation’ step of PCR
the DNA is reheated to approx. 72°c to allow for Taq polymerase to work optimally as nucleotide bases are constantly available for the new strand to be created
what is Taq polymerase and its role
it is a heat-resistant DNA polymerisation enzyme that amplifies the single-stranded RNA molecule by attaching nucleotide molecules (CBP)
what are forward primers and its role
they bind to the START codon of the 3’ end of the template strand which allows Taq polymerase to attach and synthesise a new strand of DNA in the same direction that RNA polymerase would function
what are reverse primers and its role
binds to stop codon at 3’ end of the coding strand and causes Taq polymerase to synthesise a new DNA strand in the reverse direction that RNA polymerase would function
