2.1.2 Copying our Genes
What does extending do?
allows Taq polymerse to attach at each priming site and extend (synthesize) a new DNA strand Taq polymerse begins polymerization, adding nucleotides to the 3' end of each primer attached to a DNA strand
What is the temperature for annealing?
50-65 C
What is the temperature for extending?
72 C
What are samples heated to in denaturing?
94-96C
What is the second step of a PCR reaction?
Annealing
Polymerase Chain Reaction (PCR)
a lab technique that produces numerous copies of a specific segment of our DNA in a relatively short period of time three step process; produces identical copies of the target sequence harnesses the power of an unusual enzyme derived from bacteria that thrives in hot springs; bacteria live in an extremely hot environment, the pcr enzyme, that helps replicate DNA, withstands the hot temp to complete PRC
Buffer
a solution used to incubate the reaction component
Taq polymerase
a thermostable enzyme used to extend DNA
What does PCR allow scientists to do?
allows scientists to amplify tiny amount of DNA to detect pathogens, to detect trace amounts of DNA at crime scenes, and to diagnose genetic conditions
What does annealing do?
allows the left and right primers to anneal to their complementary sequences the primers form hydrogen bonds, or anneal, with their complementary sequences in the target DNA
Thermal cycler
an instrument that automatically cycles through different temperatures used to complete PCR reactions
gene
controls production of a protein, which ultimately affects a trait in your body
What do the primers in PCR do?
designed to bracket the DNA region to be amplified
Primers
designed to correspond to the start and end of the target DNA being amplified
What is the first step of a PCR reaction?
denaturing
polymerase enzyme
enzyme that helps replicate DNA
What is the third step of PCR?
extending
dNTP
free deozyribnucelotides needed for extension
What is happening during denaturing?
heat denatures the DNA, breaking the hydrogen bonds that can hold strands together
Note:
only two of the double-stranded copies consist of just the target fragment, the others also include flanking DNA regions
What is denature?
separate the target DNA into single strands
What happens after one complete cycle?
there are two double stranded copies of the target DNA
