Chapter 8 Flashcards
To memorise and score the test
What is the purpose of PCR?
To synthesize a large number of copies of a specific gene or DNA sequence
What are the components required for a PCR reaction?
- Template DNA
- A pair of DNA primers
- Taq polymerase (or another thermostable DNA polymerase)
- Deoxynucleoside triphosphates (dNTPs)
- Buffers
- MgCl2
- Thermal cycler
How does DNA polymerase contribute to the PCR process?
DNA polymerase, such as Taq polymerase, builds a new DNA strand in the 5’ to 3’ direction using the template DNA. The newly-polymerized molecule is complementary to the template strand and identical to the template’s partner strand.
What are the three steps involved in a PCR cycle?
- Denaturation
- Annealing
- Extension
What is the role of Taq DNA polymerase in PCR?
Taq DNA polymerase adds nucleotides to the 3’ end of each primer during the extension step of PCR. It is ideal for PCR because it can withstand the high temperatures required
How does a thermocycler contribute to the PCR process?
Raises and lowers the temperature of the metal heat block at each step, allowing for denaturation, annealing, and extension of the DNA
What is the purpose of gel electrophoresis in post-PCR analysis?
To analyze the PCR products. It separates the amplified DNA fragments based on size, allowing researchers to visualize and analyze the target DNA
What are some applications of PCR?
- DNA sequencing
- DNA profiling
- GMO analysis
- Detection of pathogens in food and diseases like HIV
- Applications in agriculture, medicine, forensics
Why is it important to perform a negative control in PCR?
Performing a negative control (no DNA) helps validate that the PCR product is amplified from the intended DNA and not contaminated by other sources of DNA
