BME100 s2015:Group17 12pmL4
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LAB 4 WRITE-UP
PCR Reaction Sample List
DNA Sample Set-up Procedure
--Thermal Cycling Program--
--> Denature at 95°C for 30 seconds, Anneal at 57°C for 30 seconds, and Extend at 72°C for 30 seconds
Research and Development
PCR - The Underlying Technology
Q.1 What is the function of each component of a PCR reaction?
A PCR reaction is made up of several components, such as template DNA, primers, tag polymerase, and Deoyribonucleotides.Each of these components have a unique function. Template DNA is what the newly generated DNA is replicated from (serves as a blueprint for PCR). Primers attach to the specific sites on the DNA strangs that you want to copy. Tag polymerase carries out the replication process, like typical DNA polymerase, but Tag tolerates heat for the PCR. Finally, deoxyribonucleotides provide the PCR process with the "building blocks" to create new, replicated DNA.
Q.2 What happens to the components (listed above) during each step of thermal cycling?
There are six steps to thermal cycling. The initial step, where the temperature is 95 °C for 3 minutes, heats up the DNA preparing it for the imminent denaturation. Then, the denaturing step (where its 95°C for 30 seconds) is where the DNA strands are split from each other. Then, the annealing step, where the temperature is 57°C for 30 seconds, happens before the two strands of DNA template rejoin, and where the primers are attached to the target sites. The next step is to extend (72°C for 30 seconds). This is where the tag polymerase is activated, which then finds the primers. The final step (72°C for 3 minutes) is where the tag polymerase begins adding deoxyribonucleotides until it reaches the end of the strand. The final hold (at 4°C) is when the overal PCR reaction comes to a halt.
Q.3 DNA is made up of four types of molecules called nucleotides, designated as A, T, C, and G. Base-pairing, driven by hydrogen bonding, allows base pairs to stick together. Which base anneals to each base listed below?
Q.4 During which two steps of thermal cycling does base-pairing occur? Explain your answers.
Base-pairing occur between the steps of Annealing and Extending. During Annealing, the temperature is dropped to 57*C, which allows for the primer to attached to the separated DNA strands. The temperature is then raised to 72*C which enables the DNA polymerase to attach to the primer. Then, the DNA polymerase acts as the expediter to attached complementary nucleotide bases to the corresponding bases in the original DNA strand. Annealing and Extending combined act as the steps for base-pairing to occur.