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