pcr Flashcards
what is pcr stand for
polymerase chain reaction
what is pcr
biomedical technology which amplifies short lengths of DNA into multiple copies
pcr is an artificial form of a natural process. what process
dna replication
what are the factors that pcr is reliant on
dna strands have a 5’ end and a 3’ end
DNA only grows from the 3’ end.
bases pair up according to base pairing rule
what is the 5’ 3’ rule
dna polymerase can only add nucleotides by complementary base pairing from the 3’ end of the strand.
how does pcr differ from natural dna replication
pcr uses primers
chromosomes cant be replicated, only short DNA strands
heating a cooling is needed for pcr
describe the pcr process
dna sample is mixed w nucleotides, primers, taq DNA polymerase
denaturation of dna- heated to 95 degrees to break hydrogen bonds between complementary base pairs and denature DNA to two strands of DNA
ANNEALING (68)- mixture is cooled to 68 degrees, so primers can anneal to each end of the two DNA strands by hydrogen bonds to give each end a small double stranded molecule
ELONGATION (72DEGREES)- taq DNA polymerase can now bind to the end when there is double stranded DNA- then catalyzes the addition of DNA nucleotides to the single-stranded DNA until a new double strand is generated
process repeats multiple
what is the optimum temperature of taq polymerase
72 degrees
in pcr, it is heated up, why is it needed to be heated
to break the bonds between nucleotide complementary base pairs
and to denature the DNA into two strands of DNA.
the pcr mixture is cooled, why
so primers can anneal to each end of the 2 strands of DNA to produce a small segment of double-stranded DNA on each side of the strands
pcr is a cyclic process what does that mean
repeats same process multiple times
what temperatures are for the three steps
95- DENATURATION
68- ANNEALING
72- ELONGATION
during pcr, if the temperature is 68, what step is it
annealing of primers
temp is 95 what step is it
denaturation of hydrogen bonds between complimentary base pairs between the double stranded dna
to produce two separate single strands of dna
temp is 72 what step is happening
elongation and taq polymerase
what type of bacteria provided Taq polymerase
thermophilic bacteria, enzyme taq is stable at high temperatures.
what is the optimum temp of taq polymerase
72
how does dna increase in pcr
exponentially- 1-2-4-8-16-32-64
doubles everytime
why do we need pcr
if the dna sample is too small (exam)
why is taq polymerase beneficial
it has a higher rate of dna replication
